NTXOlds

I serviced the badly leaking Jetaway in my '68 Cutlass 350 2bbl, but it appears that there is still a big leak in the front seal. I really do not want to put any more time, effort or money in this Jetaway, and I had my highly recommended transmission looking for a 200-4R for more than a month. They have not been able to find one yet. They said that they can put in a freshly rebuilt TH350 with a one year warranty out the door for $1100.

Looking for your advice. Should I:
1) Replace the seal in the Jetaway and wait for a 200-4R (or try some kind of stop seal in the trans)?
2) Try to find a good 200-4R elsewhere?
3) Go with the TH350?

Sugar Bear

If you can wait and afford the 200-4R that is the best performance upgrade. If you will drive the car a lot and may want to lower the rear axle ratio (higher number) in the future for acceleration wait for the 200-4R.

If you're seeking some period correct originality go with the TH350, a big improvement over the Jetaway and an available option at the time.

If a general daily driver I'd go with the TH350 for simplicity and originality to the period.

Good luck!!!

NTXOlds

That is great guidance. Thank you.

Sugar Bear

Whichever transmission you pick, ask about on this forum which converter stall speed would be best. The right choice makes a big difference, don't go with an unknown stall speed.

Posting your tire size, rear axle and any modifications will help in the selection

NTXOlds

Good point. The engine is the stock 350 2bbl, but I intend to rebuild it somewhere down the line. I am running 225/70R14 tires, and the car currently has a 2.78 open rear end. I hope to upgrade the rear to a 3.23 posi and do a mid-range street build on the engine, but since both of these changes would be somewhere down the line, I was thinking to go with the stock torque converter until the engine is rebuilt.

Sugar Bear

It is common for transmission shops to install rebuilt transmissions with a rebuilt converter of an unknown stall speed. Try to find out what the stock stall speed should be and specify that to the transmission shop, this way you'll know that the performance for your application was optimized.

Good luck!!!

Sugar Bear

I'm not the person to recommend the specific stall speed, other members have more experience in that. They will chime in.

NTXOlds

Thanks, Sugar_Bear! Those are good considerations.

JohnnyBs68S

While I doubt the OP is interested in maintaining the appearance of factory original options, the TH350 was not offered w/ the 350-2bbl until '69.

My recommendation: If you are sticking w/ a relatively tall rear gear (3.28-ish), you probably don't need the OD provided by the 200-4R. I had the same original drivetrain as the OP but went w/ a 3.90 rear w/ the 200-4R and a lock-up TC. Highway RPMs didn't need to be any lower than the original Jetaway / 2.78, and even with a 3.90 rear they aren't. Combining a 200-4R w/ a numerically low rear ratio may result in bogging when cruising around town in 4th. Of course you could always drop it to 3rd until you get above ~50 MPH.

OTOH, ~$1100 for a TH350 installed w/ a warranty would be pretty tempting, you'll notice a much better launch off the line vs. the Jetaway, even w/ the 2.78s.

Also, if you are planning on significant power increases, be sure you get that 200-4R built right to handle the power. A stockish rebuild won't last long. Good luck.

matt69olds

Do you have a 350 to install? Do you need the car now? If the answer to either question is no, go with your long term plans. No point in buying 2 transmissions.

The 350 will basically bolt in, no modifications needed. And with your current gear ratio, it’s probably the better choice.

If your positive you will eventually swap rear gears, and have no plans for big power upgrades, bite the bullet and spend the money for the overdrive.

There is no reason a properly rebuilt 2004R won’t live behind a mild 350. They really aren’t as bad as everyone thinks. I have run stock (other than a shift kit and servo upgrade) behind low compression smog big blocks. Anyone who says otherwise probably doesn’t know what their doing, or is just repeating the same bull story they heard from someone, who knew someone who blew up their 2004R backing out of the driveway, causing a fireball that burnt 6 city blocks to the ground......

I’m done now. 😏

oldcutlass

A 200R4 will not be happy with a 2.78 year ratio. I would go with the T350 if 90% of your driving is not highway.

Bubba68CS

Pretty sure most of the land barges these things came in had those gears (or worse) and anemic 307s....

I will never understand people who expect to use top gear at 30 mph. Nothing wrong at all with having a highway gear and the beauty of most automatics (200-4rs included) is you can make it a two or three speed with a click of the shifter.

My $.02, do NOT compromise on the transmission you ultimately want. Going with a stop gap is a waste of money unless you really need the car drivable - my own lesson learned.

NTXOlds

All great advice guys. I called around and found a transmission shop that said that they could source a 200-4R and install it for around $3000 out the door with a 3 year warranty. I will pass on that for sure.

Honestly, the TH350 is a great transmission and will be a perfect fit for the car as is, and if I do find myself wanting that overdrive at some point in the future, I can take the time to find one and do it on my schedule rather than as urgent replacement.

Thanks, everyone. Making the appointment for the TH350.

pettrix

A 3.73 or 4.10 gear will put less stress on the engine and drivetrain than a 2.78 or 3.23 gear does. The numerically higher gear is "free" torque multiplication and allows for the engine and drive train to work less to get the vehicle moving.

A properly built 2004R will run you around $2k for your application (max 500HP/400 TQ).

Gpc1

Sourcing a 200r4 shouldn’t be that difficult. I bought one from a pick and pull wrecking yard for about $100 from a 85 Cadillac fleetwood. It worked good until I burned up the clutches. Had it rebuilt with all the good clutches, servo and shift kits. That was $1400 but I pulled it and re installed. I used red line C6 synthetic to insure oil won’t overheat again. Car did have 2.78 gears before tranny rebuild now sporting 3.90 posi. What a huge difference this car is now fun to drive even with a 350. 400 motor going in next year!