putting a sbc in my 87 olds cutlass that had a 307

[bryguy39]

here is my question, im running a turbo350 trans,now will i need to shorten the driveshaft or get a different one? and what cross brace shall i buy? thanks in advance. Bryan

 

[dan2286]

What was the original trans???

 

[bryguy39]

i belive its the 200, its been a while since ive got to work on this car and its finally time to do it, it has dual exhaust and will have headers. i need to know what trans brace to use. thanks Bryan

 

[dan2286]

Use the cross member you have now, they are the same. I am pretty sure you can use the same drive shaft also.

 

[bryguy39]

will the driveshaft have to be shortened or will it be fine the way it is?thanks bryan

 

[dan2286]

will the driveshaft have to be shortened or will it be fine the way it is?thanks bryan

I think the difference is very minor and you can still use it. I am not positive because I have never done it, but that is what I have been told.

 

[DrRansom442]

Metric and th350 use the same mounts and same driveshaft ... are you sure you don't mean you have a 200-4r the overdrive? and if you do why replace it with a th350? Unless the trans is blown you'll be happier with the .67 4th gear ... not to mention most G-body 200-4rs had universal Chevy/B-O-P patterns. Suppose it's too late to talk you out of the Chevy lol. BT W you'd know if you had the 3 speed 200 Metric .... says it right acrossed the pan.

 

[85 Cutlass Brougham]

All G bodies with the same wheelbase use the same driveshaft, regardless of the automatic transmission they came with, so long as they have the common 7.5 axle. I have a TH 200 4R in mine, and I used the TH 200C driveshaft in it with no problems. The TH 350 is also the same length. The only reason to need it shortened is if you are running a TH-400, TH 700R4, or a manual like a T-5, T-50, Saginaw, T-10 or Muncie. The only manuals to ever come stock in the G body were the T-50 5 speed and the Saginaw 4 speed. The T-50 is a paperweight (originally used in the Monza), and the Saginaw has poor ratios, IIRC. The T-5 is usable, but not very strong. It requires a 3 inch shorter driveshaft, all things being equal. A swap to an 8.5 rear axle requires a one inch shorter driveshaft than a 7.5 rear axle, all other things being equal. So, if you swap to a T-5 and 8.5, you need a 4 inch shorter driveshaft.

 

[Blake442]

All G bodies with the same wheelbase use the same driveshaft...The only reason to need it shortened is if you are running a TH-400,...

I went from a 200-4R to a TH400 and didn't need to shorten my driveshaft, just change the yolk.

 

[DrRansom442]

All G bodies with the same wheelbase use the same driveshaft...The only reason to need it shortened is if you are running a TH-400,...

I went from a 200-4R to a TH400 and didn't need to shorten my driveshaft, just change the yolk.

I always heard it as 200 Metric/TH350 are the same but the 200-4r is longer ... one uses the 200-4r crossmember with the th400. I'd guess the two are the same length ... I wasn't 100% sure so I just swapped my driveshaft for the one that came out of the 200-4r car .... I honestly did not compare lengths though