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favorite automatic transmission, for sbc, street?

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i realize my question is kinda vague but any help would be greatly appreciated. im finally tossing the 250 that was in my 72 for a 350. it currently has a powerglide, but i wanna swap that too. i know i will need to make or get a custom cross member for almost any different trans, but what do i need to measure to figure out if i need a long or short one? they only typically come in two lengths, right? can i go with the 700r4? im hearing a lot of good stuff about the 200r4's but i dont have tons of $$, and cant find a cheap used one. i guess what im generally asking is what are my options, and what are their major differences? thank you for your time.

oh im not sure what year the block is, but its freshly rebuilt, 0 miles
 

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i realize my question is kinda vague but any help would be greatly appreciated. im finally tossing the 250 in my 72 for a 350. it currently has a powerglide, but i wanna swap that too. i know i will need to make or get a custom cross member for almost any different trans, but what do i need to measure to figure out if i need a long or short one? they only typically come in two lengths, right? can i go with the 700r4? im hearing a lot of good stuff about the 200r4's but i dont have tons of $$, and cant find a cheap used one. i guess what im generally asking is what are my options, and what are their major differences? thank you for your time.

oh im not sure what year the block is, but its freshly rebuilt, 0 miles
Based soely on price a 700R4 beats a 200R4 hands down as there are ten times more 700R4 trannies in the world. The 700R4 was based upon the old TH350 by adding a gear that makes the overall length longer. The 200R4 was based upon the earlier 200 Metric transmission (which was used behind the Vega four cylinder motor) and the added gear only made it the same length as the PowerGlide (and the TH350 or four speed). It took Buick a lot of trial and error to bring the weak Metric 200 up to handle the power of a V-8 or turbo powered V-6 when it was used as the 200R4.

The 700R4 in it's last itteration before morphing into an elecronic controlled transmission is the version you want as earlier years were weaker (every year the tranny was redesigned and improved to reduce warranty claims). The case is longer and the mounting point is moved to the rear because of that. So you will need to shorten your drive shaft in addition to modifying or replacing your crossmember. With an overdrive you can increase the rear gear ratio (actually may have to if your rear gear is too tall) to improve performance without hurting the economy you enjoy now.

All Nova and Camaro and Chevelle transmissions will have a short tail shaft (six inches long). Big heavy B-body cars (caddy, Buick, Olds, Impalas, etc) and light trucks have a long tail shaft that is nine inches long.

Big Dave
 

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I guess it really depends on what you're trying to do here. I prefer my good old muncie M21, but that's just me. The 700r4 is the obvious choice but the old THM350 will bolt right in and consumes less horsepower and are easy to get.
I also have a Buick skylark GS clone I'm building. The Buick guys are telling me if I want to change from the THM400 (which I love BTW) to use the 200r4 instead of the 700r4 if I want OD. I suspect may be a little biased as there are no BOP 700r4's.

If you have a tall rearend gear and lots of torque, use a 350 or 400, If using a lower rearend gear or less torque lower in the rpm band and want OD, use the 700r4 IMHO.

Clear as mud?
mpv
 

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The 700R4 for sure, 87 and later!... OH, and to make it super simple, full manual and toggle switch for the lock up!...
 

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No electrical, no adjustments, just 2 wires for the toggle!.. What happens if you forget to unlock the converter?, same thing if you don't push the clutch in on a manual tranny!..:D
 
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