I'm in the process of swapping out the Jetaway in my '68 Cutlass w/ a 200-4R "Street/Strip" build from CK Performance. I did alot of research prior to starting this swap and pretty much everything I was aware of (crossmember has to slide back ~6.5", etc). A couple of items that had not been talked about much regarding this swap are:

1) Trans mount bolts in the 200-4R are not same thread as in Jetaway, so I can't re-use the old bolts. I ordered a new trans mount which came w/ new bolts for the crossmember, but not new mount-to-trans bolts.
UPDATE: The 200-4R trans mount requires metric size M10 x 1.50 x 35mm long bolts

2) Parking brake cable will need to be "adjusted" to fit the new crossmember location. The intermediate cable will need to be shorter (new ones avail at Rockauto), and the front brake cable will need to be longer. Once I figure out what lengths I need, I'll post that info too.

3) The 200-4R shift shaft requires a metric size M10 x 1.50 thread nut.

As I progress w/ this swap, I'll post up any other unforseen obsticals and solutions I used.

 

Google is my friend. Trans mount bolt size (mount to trans case): 10x1.5x30 or 35

Metric, that figures.

 

Brake cables will be TH400 length. Primary cable pretty important to be correct longer length for xmbr clearance. You can shorten up the secondary & terminate it w/ a cable stop, generally just on one side w/ original stop on the other side.

All the threads except maybe the pipe thread on cooler line adapters (maybe selector shaft too) are metric. Converter bolts are metric too.

 

I posted under (Putting a 200R4 in my 65) that shows a lot of the things I did to get it to fit and work properly. I got mine to fit and work perfect.
You didn't state what engine or carb you have, the TV cable is the most important thing to get hooked up properly, I also added a second 16,000 oil cooler and a deep pan so I could get a good bottom pickup filter, I also had 200r4 converted the a non lock up converter which made the installation very easy to do.

 

'Cause the big "METRIC" on the bottom of the 200-4R trans pan wouldn't have given it away...

The need for different e-brake cables has been noted many times here. Get the front and intermediate cables for a TH400 car with the same wheelbase (112" for 2drs, 116" for 4drs and flattops, 121" for Vistas). They are available from RockAuto.

 

DOH! I haven't actually taken a look at the underside of my new trans yet, its still sitting on the dolly, but I would've gotten there eventually!


Yeah, I'm learning there is alot more valuable info here on CO than generic Google searches leads one to believe. I checked out all the cables at RockAuto, but they seem to put all available sizes into the "list" regardless of which motor you select when drilling down the search (and the application discriptions between the various parts supplies are not consistent leading to mass confusion within my noob mind. I'm just going to measure what I have and get an intermediate cable ~12" shorter, and a front cable ~6" longer. Now if I can just figure out how to get that front cable out..... (heading over to my other thread to check out replies now.......).

350-2bbl. I got the TV-EZ kit for a 2bbl Rochester from BowtieOverdrives which includes a carb adapter, so hopefully I'm all set. Also ordered their install kit which includes an inline filter (great place to tap in an external cooler while I'm at it) and pressure gauges to get the TV-cable setup properly. They have pretty detailed instructions.

 

You will like BowTies kit, mine worked perfect out of the box.
I know Joe always preaches changing the cables but if the head bean counter at GM had figured out all they need was .50 worth of hooks instead of stocking 2 totally different cable set ups, cars would a TH400 would have had a couple extra hooks instead.

 

All I will say is that GM car design was and is ruled by the beancounters. I guarantee that if they felt there was a way to use the same parts, they would have.

 

Made some good progress this past weekend:

Shift linkage: I used a Kugel KK02 shift linkage to connect my column shifter and replaced the factory double-hinged linkage that pivots off a point on the frame. Since the swing of the 200-4R shifter shaft rotates ~76 degrees (from "P" to "1") while the Jetaway rotates only ~60 deg (from "P" to "L"), the Kugel kit allows you to change the ratio so that the column shifter movement stays about the same. While the indicator markings may not line-up properly (nobody makes a new shift indicator for a '68 Cutlass....Novas and Camaros yes, but not Cutlass), at least I can get it aligned so that the neutral / park safety switch and the Reverse safety gate still works. One trick to accomplish this required me to deviate from the enclosed instructions. Instead of placing the column shifter in "Park" and installing the kit that way (and hoping I made the ratio conversion correctly on how far out on the trans lever to bolt the Kugel arm), I placed both the column and trans lever in "N" and adjusted the shaft accordingly and installed it at a point on the arm that gets a similar swing. Now the gate on the column that prevents me from accidently knocking it into "R" from the "N" / "D" positions is alligned properly w/ the "N" position on the transmission and works as intended. No, the indicators on the column don't quite align properly, but I can "feel" all shift positions and the safety gates for "R" and "Park" work as intended.

Another big advantage of this Kugel kit is that it gets rid of that factory linkage that probably is in the way for adding headers later on. Also, this kit comes w/ the special bolts that holds the lever / serrated adapter to the trans selector shaft (both metric and std thread versions), so you don't have to worry about that part.

Dipstick tube: Lesson learned: TEST FIT THIS SOB BEFORE YOU INSTALL THE TRANS INTO THE CAR!! I made the stupid assumption that a new dipstick tube would fit properly. Problem is, this is a GM "generic" tube that is designed to fit multiple transmissions, and probably none of them properly. The old tube from the Jetaway won't work since its "snout" at the trans end is quite a bit different. The instructions that came w/ the new tube said to remove 1-1/4" of the tube so that the stick would read properly on a 200-4R. OK, that was the easy part. Now snaking it down to the trans wasn't too hard, but the "snout" was not aligned w/ the port on the trans and required some amount of "gentle bending without kinking" to get it lined up to the point of fitting fully into the trans port. Then the bracket at the top that ties into the top trans-to-engine bolt on the passenger side needed "friendly persuasion" to line-up properly. I spent probably 4 hours wrestling w/ this SOB to get it to fit the snout into the trans port, and it is still probably hitting the trans tunnel in the floor pan. Compared to the tube on the Jetaway, which is curved really nicely around the bell housing and attaches at the trans bolt perfectly, this "generic" replacement tube is a PITA.

Lockup Solenoid Electrical Connection: I reused the Jetaway's kickdown solenoid wire to connect the 200-4R's lockup. I'll have to rewire the other end under the dash later, but at least the bottom end is connected and I didn't have to drill a hole in the firewall and route a new wire.

TV Cable: The TV-EZ kit from BTO I'm using included a spring that goes under the TV plunger that their instructions claim "MUST" be swapped to work properly w/ their TV-EZ kit. So that required dropping the pan and removing some parts to get this plunger out and swap springs. Not too difficult, just a little time consuming. This also provided an opportunity for me to figure out how to attach the darn cable to the trans' TV lever / rod (this was not spelled-out or shown pictorally in BTO's instructions). Theres a little rod w/ the end bent 90-deg that sticks up out of the TV connection hole, this slips into a small hole in the tip of the TV cable, so when the throttle tugs on the cable, the cable tugs on this rod and moves the lever & plunger inside the trans. This connection can be made w/o dropping the pan.

Still to go:
1) Driveshaft (after install of new U-joints and polishing up the yoke a tad)
2) E-Brake cables (need to order the shorter intermediate cable.....GOOD NEWS: It looks like the front cable may be long enough to reach the new cable behind the cross-member so I can avoid screwing around w/ that.
3) Cooling lines / External Cooler: Seriously considering all new braided lines to replace the old hard lines
4) Carb-end of TV cable: May end up w/ a entire carb rebuild at this point....but after the time spent on that dipstick tube, maybe not.
5) Rewire other end of lockup wire under the dash.

 

I do believe that hooking the lock-up to that old solenoid is only going to try and lock the converter when you floor it, which is pretty much the opposite way you want it to work.
I used 1/2 of the 2004r dipstick tube and 1/2 of the original tube and connected them with a short piece of hydraulic hose, cut the stick to the right length everything fit perfect and looks stock.

 

Indeed, I need to disconnect the other end of the wire from the existing kickdown switch and connect it to the lockup circuit I got from BTO (basically a relay connected to the brake lights that disconnects the L/U solenoid from +12V when you hit the brakes). The trans already has an internal switch in series w/ the L/U solenoid that prevents it from lockup until it shifts into 4th gear. Hopefully, that simple system works OK, otherwise I may need to add a vacuum switch to disengage it on throttle tip-in. Apparently B&M sells a much more sophisticated lockup controller that has a speed sensor that allows you to control lockup based on speed too. That one has a speed sensor that connects between the speedo cable and the trans. More complicated, and not cheap either.


Not a bad idea, wishing I'd have thought of something like that. I had seriously considered cutting the new tube short enough so that my old stick would be the correct length, but the underside of the top of my old stick was looking kinda beat up so I decided to use the new (~5" longer) stick. Makes it a little easier to get to as well (no more wrestling with heater hoses to get to the dipstick).

 

Apparently B&M sells a much more sophisticated lockup controller that has a speed sensor that allows you to control lockup based on speed too.
I also tried this B&M setup and it didn't work any better than all the other crap people say works. You are lucky that you live in Indiana where it's pretty flat, you may get something to work pretty well, I live in the mountains and that lockup stuff without a computer just wouldn't cut the mustard.

 

might be a good place for tapping a cooler but you need to install the pressure gauge in the 1/8 port above the shift input on the driver side if you want good info.

 

Roger that. I didn't mean to imply I was going to tap the pressure gauge into the cooler lines, but I can see how the way I worded it was misleading.

If worse comes to worse, I'll install a switch to disable the lock-up when it gets annoying. If I get really desperate, I can always use a Raspberry PI computer and program it the way I want.

 

Progress this week:
1) Got the U-joints out of the driveshaft, cleaned up the shaft and yoke and sprayed some Eastwood Chassis Black on them. Should get the new U-joints installed tonight and slip this assembly back into place on the car. The measurement from the 200-4R's flange at the output shaft to the C/L of the rear axle yoke saddle was identical to that when the Jetaway was still in the car.
2) Got the shorter intermediate and longer front E-brake cables on order, should be here Friday so I'll tackle it this weekend. The assembly manual shows that the front cable goes through a slot on the cross-member when its back at the TH400 location. The existing cable reaches through this slot but goes only ~1.5" past the x-member, which may not be enough to meet up w/ the intermediate cable, thus I've ordered the longer front cable. I'll also probably remove and clean-up the two clips that connect the intermediate cable to the two rear cables while I've got this all apart.

Also got the dipstick tube pried away from the floorpan/trans tunnel, hoping a ~1/4" clearance is enough to avoid rattles.

 

Progress:
Got the new shorter intermediate e-brake cable installed OK, sure enough the existing front cable is ~ 6-8" too short. I went ahead and purchased the longer front cable in case I needed it, so I started removing the old one. Removing the clip that holds the bottom of this cable to the frame came out no problem, but was having difficulty getting the pedal-end that goes through the floor board out. Loosened the LF fender and wheel well so I could get my arm up between the wheel well and firewall to pull on the cable sheath (after pinching all the tangs on the inside w/ a 9/16" 6-point deep-well socket....tried an open end too, it didn't seem to compress the tangs quite as much) and she wasn't coming out. I got up under the dash again to try to push it through from inside, but because I can only access the driver-side foot well from the passenger side due to how I've got the car parked on the lift w/ the driver door up against one wall, I was finding myself to NOT be the contortionist necessary to pull off this job. Thus, the completion of the e-brake cable re-configuration will have to wait until I've got the car running again and can pull it off the lift and out into the driveway. If worse comes to worse and I'm unable to get the old cable out, I'll just lengthen the other end of it w/ a threaded sleeve and all-thread to reach the intermediate cable.

Got the new trans cooler installed and plumbed. I used a Hayden 404 cooler and strapped it to the (aftermarket under-dash) A/C condenser coil. As I was doing this, I noticed my radiator is beginning to seep coolant, so that's another project for the not-too-distant future. In the meantime, by NOT strapping the trans cooler to the radiator, that future project should go a little smoother. All that is left to do now is to flush the cooling lines and connect them to the transmission (need to be careful as the 200-4R coolant ports flow reverse compared to most other transmissions: the upper port flows OUT of the trans, IN to the lower radiator port, then OUT of the upper radiator port and IN to the lower trans cooler port, then OUT of the upper trans cooler port and back IN to the lower trans port).

Began tackling the TV cable hook-up to the carb. I'm using the BTO TVEZ kit for a single Rochester 2-bbl (the only kit they offer for such an obscure animal). The do offer kits for both Chevy and Pontiac tri-power setups, but those put the TV cable bracket on the back carb which won't work for my application. So the kit I purchased is closest to what I need, however it is for a "small flange" 2-bbl instead of the "large flange" that I need. Thus, the TV cable bracket that is suppose to slip under the carb mounting base won't work without modifications. Fortunately, the existing throttle cable bracket that mounts to the intake manifold uses mouting points (2 bolts) that works just fine for holding the new TV cable bracket (and the optional screw-on throttle cable bracket that is also available from BTO). After making appropriate measurements from the C/L of the throttle plates & existing manifold bolt holes, I was able to drill two new holes in the BTO TV cable bracket, cut off the excess that goes under the carb, and bolt it in place of the orginal throttle cable bracket on the manifold and it places the TV cable mount at the same distance from the throttle C/L as BTO intended while holding the throttle cable in almost the exact same spot (~1/8-3/16" closer to the throttle.........hopefully close enough). The BTO throttle cable bracket is thicker than the original bracket, so the plastic "clips" on the throttle cable need to be shortened in order to "clip" securely into this bracket. I started working them w/ a file and saw and never quite got them right to clip in place, however the cable is pretty short and stiff and isn't about to push out on its own. If this becomes a problem, I'll have to get in there w/ a Dremmel to cut these right (or just wrap a couple of tie-wraps around this to keep it from pushing out).

Now for the TVEZ cam that goes on the throttle shaft. The kit came w/ a new throttle linkage bracket that looks like it is intended to replace the existing bracket on the end of the throttle shaft, but it doesn't have some of the Olds-specific features like the pad that the idle-stop solenoid presses against. The new bracket does have one arm that is specifically designed to mount the adjustable TV cam that BTO provides and is the key to allowing you to adjust the behavior of the TV system. There is no way to mount this cam onto the existing throttle linkage bracket however. So I'm left to "merge" the two brackets, keeping the throttle connection end of the factory arm and attaching the new bracket (that holds the adjustable TV cam) to the original bracket at just the right angle as BTO intended for their kit to work. Fortunately, both brackets have features that makes it easier to determine what this "right angle" is; the slot for the throttle shaft and a hole for the accelerator pump rod will act as a "key" to connecting the two halves so that the radius from the shaft C/L and the TV cam, as well as the angle through which the cam assembly operates (from idle to WOT) is maintained as BTO intended. This will require cutting the new bracket and screwing it to the old bracket (after bending the accelerator return spring arm out of the way). I'll have to pull the carb apart to do this fab work, fortunately I had already purchased a carb rebuild kit and fuel filter years ago intending to rebuild the carb someday. Glad I didn't waste that opportunity earlier because I'm going to kill both those birds now.

So that is where I am, what is left to do at this point:
1) Get the TV cam mounted to the carb's throttle linkage bracket (w/ a carb rebuild while I'm at it) <--Completed 7/17
2) Reinstall the carb and connect the throttle & TV cables <--Completed
3) Flush the coolant lines and connect them to the trans <--Completed
4) Connect the pressure gauge <--Completed
5) Fill with fluid <--Completed
6) Fire it up / adjust the carb as required / adjust the TV cable / check trans operation <--Completed
7) Test drive <--Completed (needs TV cable adjustment)
8) Finish the front e-brake cable swap after I get the car off the lift and into the driveway <--Completed
9) Connect the lockup relay kit to the other end of the kick-down wire (another job under the dash waiting for driver-side access)

 

Well, finished up through step 5 above, connected the battery and attempted to start it w/ a fresh carb rebuild & 6 qts of fluid in the trans. After cranking a few seconds to get fuel into the carb, the engine fired up, sputtered and quickly stalled. Cranked it some more to no avial. Got out and looked under the hood and found gasoline sprayed all over the top of the engine! WTF? All I can figure is that the float (reused, not new) was shot and not cutting off the fuel flow into the bowl and spitting gas out the idle vent valve. I pulled the top section of the carb off and checked to be sure the float wasn't stuck and the needle valve was seating properly, put it all back together and it did the same thing. I was careful to set the float level and drop per the rebuild instructions (needed very little adjustment). So I concluded that the (plastic) float was shot.

Spent the rest of the weekend searching for a replacement locally, one of the AutoZone stores showed a float for a '68 Cutlass 350-2bbl in stock, went to pick it up and discovered that it was not the right float for a 2bbl. Even NAPA didn't stock one. Ended up ordering a brass one from the Carb Doctor and am now waiting on it to arrive.

So now the waiting begins..........

 

While I'm waiting on my new carb float to arrive, here's some pictures showing how I modified the BTO TV bracket (that was too small to fit my carb base) to work with the existing throttle bracket holes in the manifold. The first pic shows the original throttle cable bracket bolted to the intake manifold, and where I made measurements to make the bolt holes in the TV cable bracket. 2nd pic shows these measurements transferred to the TV cable bracket, 3rd pic shows the modified TV bracket, and the 4th pic shows it installed, along w/ the throttle cable attachement.

 

Here's the pictures showing how I modified the throttle shaft to attach the BTO TV cam bracket. The 1st pic shows the throttle shaft linkage bracket and how the return spring arm is going to need to be "flattened" out to clear the new TV cam bracket. The 2nd pic shows the first cut on the TV cam bracket that was supplied w/ the BTO TVEZ kit. 3rd pic shows how the slot for the shaft in the TV cam bracket must align with the slot for the throttle plates (the drill bit is going through the holes for the accel rod, which helps align the two brackets). 4th pic shows the completed throttle shaft w/ the TV cam bracket attached w/ two short 8-32 screws, and how the return spring arm was re-bent away (at a lower point to clear the new TV cam bracket) from the carb base to avoid interferrence, and how the TV cam bracket needs to be trimmed to clear the original hole for the rod that actuates the accelerator pump.

 

While I'm at it, here's a few pics of how I rigged the lifting of the new trans into the car while it was up on my lift (the old one came out the same way, just reverse sequence). The scissors trans jack was from Harbor Freight, about $85. The lift was at the 2nd-from-lowest stop in these photos (this allowed the scissors jack to be further extened so that it has more cranking leverage than if it was near bottomed out). My FIL and I lifted the new trans onto the jack (which was already on top of the plywood platform and jack stands) while the car was way up in the air, then the car was carefully lowered down to this position, then the trans was raised the final few inches to align it w/ the engine and get her bolted up.

 

Carb issues preventing me from getting this new transmission checked-out and my car back on the road:

https://classicoldsmobile.com/forums...ding-help.html

What should've been a straight forward carb mod/rebuild is costing me 3 weeks now.

 

Why in the heck didn't you upgrade to a Quadrajet? You don't like better mileage and power. Carb issues blow, sorry for your issues.

 

Funny guy. I'll get there, eventually, just not this round.

Well, got my carb issues sorted out and she's running again! Topped off the fluid after a few mins of run-in. Took it for a spin around the block and it doesn't really want to shift (or its a way lazy 1-2). I think I need to play w/ the TV cable cam (I currently have it set at the middle of the adjustment range). My pressures at idle are all around 100 psig in every gear, and they go up to 200 when driving. I think shifting to 1 it drops to 50, but it goes back up as soon as I press the gas. Ran the shifter through the gears, didn't really do much since it seemed happy staying in 1st .

Got my front e-brake cable replaced too, definately need to loosen the fender and wheel well to open a gap to reach up there and work it out. The factory cable had some rubber gromet at the end going up through the floor board, the replacement didn't have this. I had to get creative compressing the tension spring so that I could hook the upper end into the e-brake pedal assembly, gotta love vice-grips. The cylindrical end needs to be angled in about 80 degrees to hook it into the round hole in the pedal assy. This didn't seem well engineered, however the original cable was the same way coming out. All I have left to do is adjust it and that'll be done.

A day of tweaking and hopefully I'll be good to go. <fingers crossed>

 

Well, that was wishful thinking.

I read up on the TV system some more and concluded that my accelerator pedal is not pulling the carb linkage all the way to WOT w/ the pedal on the floor. After setting the TV cable at it's initial position (fully pulled so that the TV plunger in the trans is bottomed out w/ the pedal on the floor), the TV cable return distance at idle is too short, resulting in the TV valve sitting past the edge of its pressure port (which would explain why my pressures were not jumping when I tugged on the cable).

I modified my throttle and TV cable bracket to move it back further on the manifold so that the pedal has more pull on the linkage, reset the TV cable (the pressure now increases when I tug on the cable) and took it for a test drive. FINALLY got a 1-2 shift (BARRRK!!!), and a 2-3 and 3-4 too. However, I really have to wind it out (~3500 RPM) to get it to shift. Since I don't yet have the lockup wired, no lock-up in 4th yet as expected.

Also, as this is my first experience driving an AT w/ a higher-than-stock stall (running a 1800 stall converter from BTO), it seems like there is no thrust below that RPM (I assume this is normal?).

I think I need to play w/ the TVEZ cam some more to see if I can adjust the shift properties more to my liking. I also need to verify my pressures are OK before I begin driving this on the regular.

GETTING CLOSE!!

 

Just about done. After confirming that the gas pedal does not get the carb throttle linkage to WOT, I "reset" the TV cable to its proper initial position by manually opening the carb throttle linkage to WOT (rather than using the pedal) and let the TV cable sheath pull out to its proper position. I can live without being able to get to WOT w/ the pedal, as long as the TV cable is "set" properly (full pull at carb WOT, and full return lenght at idle), I should be good. After adjusting the TVEZ cam to ~ 1/4 of the way from the least aggressive setting, I'm getting decent shift points and firmness. It'll still down-shift when I put the spurs to it.

It's still a mystery why my gas pedal doesn't pull the carb linkage to WOT, the cable attachment point is at least as far back from the carb now as it was w/ the factory throttle cable bracket. Maybe the cable has stretched over the past 46 years? In any case, when I rebuild the engine w/ a 4-bbl carb, I'll get a chance then to correct this shortcoming.

I also got the lock-up relay kit installed and the lock-up works as expected (locks in 4th & un-locks as soon as I tap the brakes). I can really "lean" on the throttle and feel the engine torque provide thrust without the RPMs shooting skyward (nice). I was able to tap into the existing kick-down switch connector wires (switched +12V source and solenoid wire to trans), adding only a ground connection and a brake light tap. I left enough wire length to add a switch easily later if needed (or I could just pull the in-line fuse that was included w/ the kit).

About the only thing I forgot to mention in this thread is the fitting of the torque converter inspection cover. I attempted to re-use the original metal cover, but one of the bolt holes didn't line up w/ the holes in the bellhousing and would've required drilling a new hole in the cover, also the rear "lip" at the bottom center extends rearward a tad and tends to interferre w/ the trans pan & gasket. I had already acquired a plastic cover for the 200-4R, so I decided to use it instead. The plastic cover still required trimming for the starter and while it had this same protrusion at the bottom rear that interferred w/ the trans pan/gasket, it was much easier to trim this plastic than it would've been on the original metal cover. It took me a couple of attempts at this to avoid the torque coverter from rubbing the plastic cover, but with persistance in trimming around the starter was met w/ success.

Overall, I'm pretty happy w/ this trans swap. Its nice to be able to cruise at 60 MPH at ~2300 RPM instead of the nearly 3500 RPM I was at before w/ the Jetaway and my 3.90 rear gear. The firm shifts really changes the "personality" of how the car drives. Once I get the engine rebuilt and "souped" up, this is going to be a blast to drive! One un-anticipated aspect of a deeper 1st gear in the 200-4R (vs. the Jetaway) is that it produces more forward thrust when stopped, making it harder to hold w/ the brakes. If I had to do this over again, I might have opted for a 3.42 rear gear instead of the 3.90, although after I rebuild my engine to get decent power out of it, I may feel differently.

Thanks for all the helpful guidance, this site is GREAT!

 

thanks for the excellent write up! i'm working (very slowly) on swapping a perfectly good th350 with the 200-4r. i bought the tci lockup kit with the vacuum switch. i don't remember seeing the brake light disengagement in the instructions, but i remember seeing that in other kits i had investigated. based on your driving experience, is brake switch relay circuit needed? i haven't installed it yet, but i thought that maybe the brake booster would cause a large enough pulse in the vacuum to cause the vacuum switch to do the same thing as the brake light relay.

 

Thanks. I don't have a vacuum switch in my lockup circuit, just a relay connected to the brake lights. When I hit the brakes, the relay activates and opens the 12V going to the lockup solenoid and causes it to disengage. The trans also has another internal switch wired in series w/ the lockup solenoid that closes only when its in 4th gear. When it does shift into 4th, it locks up virtually immediately (w/ a small, sub-second pause for the clutch in the TC to actually lock). But it usually doesn't shift to 4th until I'm close to cruising speed and back off the throttle, so its not obnoxious. The brake-activited un-lock seems to work well, if I'm just scrubbing some speed coming up to slower traffic, it un-locks as I tap the brakes, but as soon as I release the brakes (assuming I haven't slowed so much to cause the trans to downshift to 3rd), it will re-lock up immediately. Once in awhile, the RPMs will be pretty low (~1000RPM) when I let off the brake, and if the engine isn't producing enough torque to accelerate the car, pressing harder on the throttle serves up a downshift to 3rd (or 2nd) which un-locks the TC until it shifts back to 4th. It all works pretty seamlessly. I have yet encountered a situation where I wished it operated differently.

I sure that a vacuum switch actuated lock-up have a different personality. If your trans has an internal switch that prevents lock-up until its in 4th gear, you might not need a brake-actuated relay in the circuit. I'd go ahead and try the TCI kit as-is, you can always modify it later and add a brake-actuated relay later if you think it needs it.