olds 307 to chevy 350 swap

[weshole]

95tsi wrote:
Would it be benificial to get rid of the computer controlled carb and distributor for a vacuum advance dist.? Do you think it would be easier to just get a similar year impala?

Yes and Yes.

[Guest]

Ahh...I'll take the advice of wes here. The last Olds car I swapped a 350 into was a 1984 Cutlass (donor vehicle was a 1978 Chevy Pickup) and it pretty much bolted right in. I think we had one bolt on the bell housing that didn't line up, but all of the others did. The existing motor however, was not a 307 as is the case here, but was the 3.8 liter (I believe a buick motor). At any rate, I'd trust the advice that Wes provided here anyways. He's worked with them more than I have.

[weshole]

tjamz wrote:
Ahh...I'll take the advice of wes here. The last Olds car I swapped a 350 into was a 1984 Cutlass (donor vehicle was a 1978 Chevy Pickup) and it pretty much bolted right in. I think we had one bolt on the bell housing that didn't line up, but all of the others did. The existing motor however, was not a 307 as is the case here, but was the 3.8 liter (I believe a buick motor). At any rate, I'd trust the advice that Wes provided here anyways. He's worked with them more than I have.

GM used 2 different 3.8 engines back then. one is the grandfather of the 3,8 of today, the 231 cu inch buick engine which will not bolt up. The other was a 229 cu inch Chevy engine which will bolt up close to the same. That's probably what you had in there Chuck.

[Bookem]

BPO 307 ftl but if you are getting rid of the block I'll take it off you're hands.......there are some top secret missions going on in the sprint car business with those blocks. Seriously let me know if you want it gone.

[95tsi]

Well I found a th400 tranny. Will it bolt-in in place of the th200?

[weshole]

95tsi wrote:
Well I found a th400 tranny. Will it bolt-in in place of the th200?

Yup but you need a different driveshaft yoke. The th400 has a bigger input size than all the rest.

[95tsi]

Would I have to weld that on or does it just slip on? And does it just have to be a th400 yoke to fit? The driveshaft would be smaller wouldn't it?

[weshole]

95tsi wrote:
Would I have to weld that on or does it just slip on? And does it just have to be a th400 yoke to fit? The driveshaft would be smaller wouldn't it?

You will need the yoke only. Find out what it came off of and go to your local napa and tell them you need a u joint with ends for each vehicle. Ex: 1974 Chevy C1500 with a 454/TH400 on one end and the year/impala on the other. I've done this countless times when i worked at napa.

[95tsi]

Would the oldsmobile be different though than an impala? What spline is a th400? I've been looking and some say a 30or31. Thanks for all the help by the way.

[weshole]

ALL TH400's have the exact same size/spline count on the input side. The only other trans that used this size was a few select Muncie transmissions. Ex, M21 & M22 (rockcrusher).