Thread: newbie sbc400 question

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Just a note to go along with Hopper's idea. THe THM400 has heavy internals to spin. Closer gear splits and not evenly set on the planetaries. It requires more torque to drive the unit under load. Take the gears down to a more suitable set (3.50?) and strongly consider a different tranny. Q-jet is set up for???? They can be tuned to bring this set up around big time.

Originally Posted by nitrowarrior

Just a note to go along with Hopper's idea. THe THM400 has heavy internals to spin. Closer gear splits and not evenly set on the planetaries. It requires more torque to drive the unit under load. Take the gears down to a more suitable set (3.50?) and strongly consider a different tranny. Q-jet is set up for???? They can be tuned to bring this set up around big time.

With all the torque the 400 sbc makes I don't know if you would ever feel the differance but you might notice it at the track.
Keep in mind this 400 sbc is swinging a 3.75 stroke the same as the 396/402.

I'll have to wait till it comes back from the shop to check the gears; but i do have a th350 laying around that i had purchased for my regal but when my mechanic found out i had a th400 also he said i should run the th400 behind my motor, you guys think it would help if i had the 350 built and installed behind my motor. and as far as the q-jet my mechanic tuned it a little when i took it back; now i'm just trying to decide on what step to make next i think it's gonna be the gears how much do they normally cost?

It depends on what rear you have. I'd say $100 and up for ring & pinion. Then there's bearings, shims, seals...etc could be another $75 and up. It all depends on what you have and what you need....