th350 to 2004r

[blueta]

I know I don't have a turbo buick anymore but you guys are the best when it comes to transmissions so I'll ask here anyway So...Right now in my 69 bird I put in an lt1 with a th350 (bop trans). My gear ratio is 3.55. The car doesn't really feel like my old 95 t/a with very similar mods. I know the 4l60e has a pretty steep first gear but it feels different throughout the range. I also had 4.10's in the t/a. So...4.10's w/a non overdrive might be a little wild for the highway so I was considering swapping in a 200. Does the first gear in the 2004r actually feel different then a 350? I know the ratio's are close but the 200 is a little steeper (2.52 vs 2.74). Cause I would have to do the trans first and later do the gears so I would like it to feel a little snappier. Also could I just use my crossmember and the 200's mount? Or would I need a new crossmember? I know the overall length is very close so the d/s will work fine. Also if I use a 200 from a buick do I still need to use my chevy engine to BOP trans adapter? Any help would be appreciated. Thanks!

 

[A. G. Olphart]

On the theory that a little information is better than none, here goes:
You won't need the transmission adapter- take a look at the very holey front of the trans shown here (fits Chev +BOP): http://www.gnttype.org/techarea/pictureguides/tranny/thm200vs350.html

You can also see about how much farther back the 200-4R has the rear mount; are there multiple mounting holes in your frame to allow the crossmember to be slid back?

As to feeling the difference, that would depend on the sensitivity of your buttometer; the numbers show that the 200 will dig a little harder given the same stall converter.

If you are serious about this swap, read Bruce's sticky post on strengthening the trans, and get one that suits your needs from one of the board vendors. (If you gotta try DIY, buy Chris's book) Good luck.

 

[brian]

I just put a 2004-R in my 81 Malibu. The driveshaft and yoke are the same. You are good there.
You will need a x-member. I recommend "Iceman" on Malibu racing.com. Fast service, and a beautiful quality part. The trans mount is back farther, and you may need a "frame extension" (he sells those too), as I did. This part allows you to mount the member back further.
You will definatly feel the diff. The 350 is like an anchor compared to the 200. The 200 just takes less to power, especially with roller bearings inside! ;-) I also have a 4.10, and non lock-up converter, and I spin 2600 on the expressway at 70mph. (28in tall tires) Hope this helps...Brian

 

[blueta]

Awesome guys, thanks. I also have a 2800 stall sitting here from my last turbo buick for the 200 trans (currently have a 2500 in the 350) so that should help out a little also. Thanks again.

 

[Nordbert]

The mount of a 200-4r is in the same
place as TH400, so moving the crossmember rearward should work.
www.700r4.com should have all the info needed to set up the TV bracket and cable. Their www.tvmadeez.com
has a lot of good info for guys doing swaps.

 

[blueta]

Well thanks again. I forgot all about the tv cable...