I have a 350 sbc that I am rebuilding to replace a tired 307 sbc. Currently the 307 is tied to a leaky TH350. I have a good 700R4 that came w/ the 350. I'd like to go to a trans w/ an overdrive gear for highway travel and have been told the 200R4 is the same size as the TH350 and will bolt up w/o any problem. A few acquaintences have told me the 700R4 will work just as well. BUT, I'll have to reshape the trans tunnel sheetmetal to accommodate the wider and taller trans body. Also I'll have to shorten my driveshaft because the 700R4 is longer than the TH350 or the 200R4. Does this all sound right to you? I'd prefer to avoid modifying drive shafts and floor pans to get a 4th gear. Any suggestions or other ideas?

Had the same debate a while ago on this board. Went with a modified TH200R4 behind a 500hp pontiac. Factors that influenced me were the fact that the TH200 was more of a 'bolt in' than TH700R4 in a BOP pontiac application that previoulsy had a TH350. Both would have had to be modified to handle the power so that wasn't an issue. Lower first gear also on TH200R4. It works fine for me, I've had no problems. Check for bolt pattern issues if you decide to go TH200R4 and sbc 350.

I could be wrong, but I believe most, if not all 200-4R's use a dual bolt pattern.(Chev/BOP) At least mine does.
JA

It would be helpful if we knew what kind of car you have. I put a 700R4 in a 67 Camaro and there were no floor clearance problems.

not all 2004r have dual pattern bell

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At the Bonneville Salt Flats... 130mph is known as First gear ...............

Provided the 350 you're building isn't screaming hi-po, the 200 is the way to go in my opinion. Not only does it basically bolt in with no modifications, it has much more favorable gear ratios. The 700 has a super low first and a normal 2nd, which makes it the largest RPM drop of any automatic tranny on the market.

The 200-4r is also smaller, lighter, has less parasitic loss, and can be built for some pretty serious power.

I wouldn't worry about the trans tunnel. There are three basic sizes of tranny case; the 200 family, the 350/700 family, and the 400 family. Almost all GM cars were available at some point in their history with any of the above trannys, so I wouldn't worry about tunnel fitment.

I put a 200-r4 from an 85 grand national in an 80 camaro.I just drilled two new holes and moved the cross member back.The drive shaft was the same.I just had to a hook up the tv cable.
So in my experience,yes it does bolt right in where a short shaft th350 would go.
What kind of car is it going in?

i have a 200 r4 in my 83 malibu sedan. great transmission. it will bolt up to buick, chevy and oldmobile engines.

Besides the Chevy Only Bellhousing pattern and Having to shorten the driveshaft. The 700R4/4L60/E has one less negative. The 3.06 1st gear ratio is no longer a problem. PATC/TransmissionCenter.net has new 1st & 4th gear planetary gear sets. They now have 2.66 1st & .64 4th gears instead of
1st-3.06, 2nd-1.62, 3rd-1.0, 4th-.70 you can have 1st-2.66, 2nd-1.55, 3rd-1.0, 4th-.064. Don't know any prices of these new parts. my guess not cheap though.
Also there shouldn't be anymore floorpan problems using a 700R4 than with a 350 or 400. The Unibell 2004R does have a larger bell dia.
You should try fitting an TH350 between the torsion bars on a Chevy Luv P/up. Talk about tight!
http://www.transmissioncenter.net/[/url]

The vast majority have dual pattern. The rest are BOP pattern.