Reese Jacobs

Right now ive got an 85' Delta with the 307/2004R combo with a little over 60k on the clock.

I just scored a good running 73' 350/350 (#8 heads) setup with almost 70k on the clock.

Dilemma here is:

Part of me wants to keep it simple as possible and just swap drivetrain for drivetrain and rid of the CCC carb but it seems it would also require a different length driveshaft and a different crossmember and that sounds like extra money to spend.

The other part of me wants to bolt up the 350 to 2004R to retain the crossmember/driveshaft. However with that, I can either keep the CCC and mess of vacuum or ditch and then have to switch the lockup TC to a 4th gear pressure switch when I drop the trans fluid and also swap over some linkage for the TV cable.
With this, would a smog 350 be tame enough to baby the weakest variant of the 2004R trans.

Main goal in mind is to not spend a whole lotta money doing this. Dont mind the tinkering aspect of it.

Anyone experience a similar dilemma and willing to share what worked/what didnt?

olds 307 and 403

I say the 350 with the TH2004R. The CCC Qjet should work OK with that 350, just change the secondary rods and modify the secondary air door to open all the way. Everyday Performance has a conversion arm if you want to use the 73 carb and no CCC. Bigger bigger boost valves in the 2004R and a trans cooler should be more than enough to live behind a stock 73 350. There are various lock up kits, the TCI kit worked for me.

Reese Jacobs

Thanks for the suggestion. Bigger boost valves for more fluid flow? I dont know if id be super into taking the pump out to change those.

olds 307 and 403

Not necessary to remove the pump to change the boost valves, a snap ring at the bottom of the pump. Yes, the boost valves bump up line pressure.

Reese Jacobs

Ah excellent, gave a quick look on the web and it seems .500 is a popular fix and im going to assume .471 is stock? Thanks for all the info

olds 307 and 403

I believe it is .471", the regular trans like yours may be even smaller. There is also a .555 and larger reverse boost valve. I ran the .555" in a trans that was rebuilt but had soft shifts. I put it in, brought the pressure up up from 190 to 215. Nice and firm full throttle with completely stock part throttle shifts, I loved it. With the stock servo, your shifts will still be like stock. If you run the 350 carb make sure you get that adapter arm and use the 307's TV cable and set the TV cable on install. Even though there is only 70K on the motor, put in a timing set and new gaskets, including a rubber rear main seal. I believe the Felpro Olds seal is the Ford 292 seal, easiest fit. The AMC seal is harder to put in, very tight. Also seriously consider dual exhaust on your car, the stock exhaust is horribly restrictive. You can buy a block off plate for the crossover port on the passenger manifold. Good luck.

joe_padavano

Just to clarify, the short tail TH350 and 200-4R use the same driveshaft. The crossmember DOES have to change, however. The 77-90 B-body cars have an asymmetrical frame and the crossmember sits at an angle. You can't just slide it forward like you can on the earlier cars. You'd need the crossmember for a TH200 car.

olds 307 and 403

Good points Joe. What was the base gearing for the Delta 88 with a 2004R? It allows a gear upgrade which will greatly increase performance. With a 3.42 gear and assuming the 215/75R15 tires, with a TH2004R, it will run 1675 rpm at 60 mph. With a 205/75R15, figure around 1725 rpm at 60 mph. Both size tires were available, I believe.

Reese Jacobs

I was definitely considering a G-Force crossmember to accomodate both humps for duals regardless of whether it be for the 2004R or TH350. Just more $ to spend though.

My 85' has 2.73 gears. I do have a used set of 3.42 original gm gears and carrier but im going to test my skills setting up a rear using my 83' delta that only has 2.41 gears before I open up my 85'.

69CSHC

Metric 200 is the weakling not the 200-4R, should be fine with a stock 73 350.

Depending on which trans you go with, the appropriate factory crossmember can be notched and boxed for true dual exhaust.

With regards to cost effectiveness, I think just swapping in the 350 engine alone is best short-term. Long-term 350/350 combo is the way to go.

joe_padavano

News flash: Every single part in a 200-4R used for first, second, and third gears (basically, everything aft of the center support) is IDENTICAL to the parts in a TH200. Pretty much everything used for the first three gears and reverse interchange and have the same part numbers.

olds 307 and 403

Curious why the TH200C fails more often. Isn't there more clutches in the TH2004R in those first 3 gears?

joe_padavano

Both TH200 and 200-4R transmissions use configurations with different numbers of clutch plates, depending on application. TH200s behind the V6 have the lesser amount. Those behind the 307 have the same number of clutch plates as do the 200-4R in the same application. The clutches typically aren't the failure point, anyway. It's the stator shaft splines, the crappy plastic thrust washers, and other hard parts. These are pretty much common between the two. A 200-4R is just a TH200 with an extra overdrive planetary gear set and clutches between the pump and the rest of the trans. This is exactly how the 4L80E was made from the TH400. Open up this Transtar catalog and compare the TH200 and the 200-4R sections. You'll see that the parts are the same between the two.

olds 307 and 403

Interesting, we never did anything with a TH200C other than swap a TH350 in their place. Just surprised with how tiny the TH200 case is, that they share as much as they do.

joe_padavano

I didn't appreciate the commonality between the TH200 and the 200-4R until I tore apart the trans out of my 85 D88 that I'm rebuilding. I needed to replace some internal parts - the f'n plastic thrust washer between the input drum and the lo/rev clutch housing had failed and those two parts welded together, which means second gear only and no reverse. All those parts are common among the TH200, 200-4R, TH325, and TH325L4. As I got further into it, I was surprised by how much is actually common. Of course, this also means that many of the HD aftermarket parts for the 200-4R also fit those other transmissions.

69CSHC

Joe I trust your knowledge more than most and you know that. But life experience tells me different on this subject...

Exactly, have had a lot of Oldsmobile's in the family. Never an issue with the 200-4R behind a high mileage costume cruiser wagon, multiple high mileage G -body Cutlass coupes. My 87 442s original KZF is absolutely kick ***. More passes on it than my 69 with a tightened TV cable. While we had a 79 mint babied low mileage Calais in the family that needed the metric 200 replaced twice. It was a numbers matching 260 CID version.

joe_padavano

Check the part numbers. I did a spot check in the factory parts book (June 1991 printing) and while most parts are common between the RPO MV9 (TH200) and RPO MW9 (200-4R), there are interesting differences in certain applications. For example, while run-of-the-mill 200-4R transmissions use the same P/N rear planets and carrier as on the TH200, the transmissions used behind VIN 9 307s have a different P/N for this item. Unfortunately it doesn't say what that difference is, but the CK Performance book notes that some GN planet carriers have additional thrust washers on the planet gears. That might be the case here as well. In any case, the basic architecture and dimensions of parts are the same. The input drum, as an example, is the same P/N on TH200, 200-4R, TH325, and TH325L4 (P/N 8648484).

olds 307 and 403

It makes sense since guys are obviously building the TH200 for high powered cars for low hp draw can use the same billet forward drum and shaft among other parts.