TH400 Question

[Joes406]

I was just wondering how much HP/TQ a stock th400 can handle?

My 406 puts out roughly 400HP/500 ftlb of TQ at the flywheel..

Will be using a 2200stall and 3.42 gear.. will never see slicks or the track, but I wanna know I can "punch it" and not worry..

This is a frsh th400 w/stock rebuild..I was going to put in a transgo Shift kit also..

thanks

[ROAD WARRIOR]

The TH400 is a very stout transmission. You should be fine.

[Texas Hotrod]

I built a th350 that went behind a stout 406 and it worked fine. With some machine work I added an extra clutch to the packs and used a Trans-Go shift kit. It had nice crisp shifts, until I added the 671 blower. Amazingly it still shifted good, but slid a little too much into each gear for me to feel comfortable with.
For the easiest solution, I built a th400 to take its place. A basic stock rebuild w/the Trans-Go kit and it works perfectly. No problems holding 600+ft.lbs. of torque. If I swap pulleys and raise the boost, I can always turn up the screw on the modulator.

So, to answer your question: Yes, it will easily hold the torque of any small block. The only issue w/running a th400 is that it will rob your engine of roughly 50hp to run the thing.
You can gain some extra ponies just by using a more efficient th350.

[Jayco_Automotive]

the man thing to change in a 350 with hi-hp is the direct drum the oem one isnt fond of too much hp that virtually the only weak link in a 350.