700r4 swap questions.

[siggyfreud]

Originally Posted by GMCJOE

3.08’s are low for running with a overdrive transmission, and could cause it fail from overheating. 3.42 gears in my opinion are as low as you want to go. 3.73 are good overall gears for the 700r4. I have the factory 4.11’s and runs out great with my 700r4.

As for lockup, plenty of material out there to read on how to hook it up and different options for it. I personally when with a non lockup torque converter for my 700r4. I also have about 2k into my transmission from getting it built by a reputable shop. Only thing I sacrificed is a few 100 rpm’s, about 1-2 mpg, and it’ll run just few degrees higher on temp for the trans.

There were plenty of cars (C4 Corvette's for example) that came from the factory with 3.07 rears and a 700R4. My college roommate drove an 85 with that combo and it was great due to the low first gear.

Using converter lockup in overdrive will help reduce heat since the TC doesn't have to slip.

I had a 4.11 and 700R4 in my 66 GMC and it was too short for the street IMO. I couldn't maximize acceleration due to traction issues. Would have been better with different suspension, but I think a 4.11 with 700R4's 1st gear is overdoing it for most situations.