Think about this before you look for HP

[lilbowtie]

Transmissions seem to be my Achilles heel. This motor is really, really strong and the THM400 is only rated for 450 ft lbs and I think I am over that.

I'm going to suggest going through the trans yourself. The 400 & 350 transmissions are a pretty simple and there are a lot of upgrades to be installed. I'm not a trans expert but with the help of a book - How to build and modify the T-400 trans - I've built 7 of them 2 w/trans brakes and all are fuctioning well.

 

[84GP455]

Thanks. I have a large cooler on there, plus the fluid runs through the radiator.

Obviously your transmission is no good now but when you're ready I would bypass the fluid going through the radiator, the radiator is hot to begin with and the cooler that's in it is very small so it doesn't do a good job. If you have a large cooler already then it should replace the cooler that is in the radiator just block off the inlet/outlet and just use the large cooler.

 

[G_Body_Enthusiast]

I'm going to suggest going through the trans yourself. The 400 & 350 transmissions are a pretty simple and there are a lot of upgrades to be installed. I'm not a trans expert but with the help of a book - How to build and modify the T-400 trans - I've built 7 of them 2 w/trans brakes and all are fuctioning well.

what tools are needed to rebuild one? i have a th400 of unknown condition and i was thinking of rebuilding it with some upgraded parts.

 

[lilbowtie]

Love Pabst - You can get carried away buying proper tools or make due with a lot of what you probably have. If you would like I can send a list of what is recommended. What you might not have is seal and bushing drivers (I made my own) and there is a special compressor to disassemble the forward and direct clutch packs (I used my drill press) A vernier, dial indicator, and slide hammer.