Chevy/Olds transmission interchange

I have an '83 Olds engine backed by a 350 transmission, both of which need rebuilding. Instead of rebuilding the transmission, is it possible to use a Chevy 350 in place of the Olds transmission? If so, it would be cheaper to buy a rebuilt Chevy ****** than to have the Olds ****** rebuilt. Can anyone help me?

 

The bolt pattern is different. You can buy an adapter to use the Chevy trans for about $75.

 

The rebuild shouldn't cost any more for one than the other......they are both TH350's and differ mostly in the case to block bolt pattern. Internal differences, if any, will be slight. The only difference I could see occurring is if the one you have is really trashed inside and you can find a better one for a core......the cost COULD be less. But, then again, in that instance, you will have to buy a second trans and pay add'l labor to have it looked at. So, it seems to me your easiest, lowest cost option is likely to be just having the present ****** overhauled.

Ray

 

The Olds 350 and the chevy 350 trans is exactly the same except the bolt pattern. The BOP (Buick, Olds, Pontiac) trans has one bolt pattern and the chevy has its own. The internals are the same. Any shop that does transmission work can rebuild yours for the same price of the Chevy trans.

 

I thought the Olds engine had been dropped and replaced by the Chevy 350 by '83.

 

No, in 1981 they dropped the Buick 350, Olds 403, and Pontiac 301. After that you had 305 and 350 Chevrolets and 307 Olds block V8s in cars. I had an '87 Pontiac wagon with the 307. It's a boat anchor.

However, I thought that by 1983 you had 200R4 transmissions in most of your RWD cars, some of which have dual bolt patterns to them? When did they drop the car TH350?

 

i was told once that you could bolt a chevy trans to a pontiac,buick, olds or vice versa the only difference is the BOP has the dip in the top of the "bell"

i dont know who told me that but i doubted it then and i still do

i dont think the 200r4 hit accross the board until 84 could be wrong i probably am

 

noit all v8's had a 350, some were only 250's. 350's had a removable tailhousing. 83 could have had a 2004r but it was optional. the 83 307 I believe was still the flat tappet motor, the 84's had a roller cam and were quite a bit better engines.

 

Look at a dual pattern 200R4 sometime - some of the lower holes don't match up.

Of course those early 200R4s had bugs, it's entirely possible someone could have swapped in a TH350, I know a lot of 700R4s got replaced by them.

 

Well, yes and no.....I once bought a '64 GTO for parts for my good one that had a Chevy TH350 bolted to the Pontiac engine. Only one bolt on each side lined up, so it was held on by two 3/8 bolts; NOT the hot setup!

 

The lower bolts and the alignment dowel pins are exactly the same between Chev and BOP patterns. It is the second set of verticle holes that are a bit inboard on the BOP and the upper bolts are way off. However, there is a thin "adapter" plate available that permits use of either on the other block design.

So far as I know (and all I have ever seen) 2004R have have multifit cases and some (I have one) later TH350 cases are multifit.

Ray

 

Make sure it's a 350 Olds and 350 trans, as stated above that car would have had a 307 Olds and metric 200 trans. The 307 is a good crusier but might as well upgrade to a 350 or 403 if you can , a 350 will bolt right in , switching to a 400 or overdrive runs into cross member problems which can be fixed by buying new or modifiing the one you have.

 

The 4 bottom bolt holes along with the alingment lug are the same as i recall but the two top bolt holes are different. By the early '70s GM was producing both the T350 and the T400 with dual bolt patterns and they are not hard to come by.

There is no difference on the internals, some of the BOP trannies came with a lock up converter that was fairly rare in the chebby trannies. In the early '80s you could get the chevy with a lockup on the mid sized cars they had an 11" converter. Kind of a hot rod piece but if you thorw much torque at them they will explode (dont ask how i know that).

Too much info right? Just look at the bell and see if you have a dual bolt pattern ****** or look at the bell of the one you want to use.

 

He's asking about GM transmissions, not Mopar.

 

Very strange bump of a year old thread, indeed.

For future searchers, verify that the TH350 is indeed a TH350 and not a TH250 variant.