Impala Tech - View Single Post - My 61 Restore Erath County Texas
View Single Post
post #21 of (permalink) Old 03-21-2018, 07:58 PM
Big Dave
Join Date: Jan 2006
Posts: 12,756
When the 700R4 first came out a 305 would break it. GM had a redesign out every production year for the first twelve years it was made. Even the 4L60 that replaced the 700R4 was redesigned within two years of coming out and called a 4L65 because the original design couldn't handle the ever increasing torque of EFI powered 350 SBC in trucks, and the LS-x series of engines in cars with rear wheel drive.

A 383 is an entry level big block under most car company designations such as the Plymouth Road Runner (Beep, Beep). Big blocks require a bigger stronger transmission than small blocks because they make more torque. The 700R4 was rated at only 300 foot pounds of torque. If your engine makes more than that the tranny will need special parts on a rebuild to make it meet the torque load. (bigger input shafts, more gears in the carrier assembly, stronger sun shell, and a strong sprag). None of these aftermarket parts are found in a stock junkyard transmission, so you either have to buy the parts and install them your self or buy a rebuilt tranny based upon torque rating from a competent remanufacter.

I can recommend TCI, because they have a wonderful warranty program, not because they build the strongest transmission with the "best" options (such as gearing or increased clutch holding ability).

It is like saying I want a PowerGlide because all of the top dragsters have one. The Powerglide that are used in Super Comp only share the name with the stock PowerGlide. There isn't a single GM part inside the aftermarket Super Case. Every part has been super sized and machined out of solid billet unobtanium, then cryogenically frozen to near absolute zero or hardened with heat treatments.

Big Dave
Big Dave is online now  
For the best viewing experience please update your browser to Google Chrome