Anyone know how much HP the stock th400 (stock rebuilt recently) can take? and what would be needed to insure the tranny holds togeher on a 700+ hp engine? thanks
no replies... ill change it up a little bit, how much power has anyone ran in a th400 and what was the outcome?
Well, the factory thought enough of the T-400 to put it behind most every high powered and high torque power plant they've put out. The 'new' 4L80-E is more or less a T-400 with an overdrive and computer control. There are lot's of ways to make them stronger though. When I was a kid I beat the hell out of a 68 Riv with a 430 that had couple of upgrades, the stock 400 had a shift kit and nothing else. Held up great despite my best efforts to break it. Full power-braking burn-outs right through 2nd gear, max stall against the stock converter and launching that 5000lb car on the street and on the track literally hundreds and hundreds of times. How strong is it? Pretty strong. :bglasses:
thats sure reassuring, at least i know it isnt going to explode... still getting a trans shield just in case and were buying line locs, so brake burnouts are gone. but is it 650 hp strong? on our tranny upgrades "list", i see: tranny cooler all new clutches all new bands new "sprag" Shift kit (trans-go or B&M) high volume filter bushing kit theres a few more things, cant find them right now thats all i have, im going to search TCI and B&M for more upgrades i might get, these ones were from poston, not sure on quality. think it would be able to sustain that much, street driving, probably street racing a few times a night, since people seem to like to challenge buicks that can whoop them... what do you think?
Don't go with just a new sprag go with an upgrade 34 element sprag, maybe more clutches as well. Then there's the light weight more expensive stuff...
Yes by all means upgrade to a better sprague. If you lose your 17 tooth sprague you'll have metal debris going all through your transmission, therefore wasting all your time and money. It's just good insurance. Especially for a full weight car. This I'd say is an absolute must !!! My .02. John
I remember reading that the 4L80E was designed very similarly to the TH400 and was capable of 885 ft-lbs. I can't guarantee that every TH400 is that strong, but it's a beefy tranny! -Bob Cunningham
were getting another tranny cooler, going to run it through both the radiator and the tranny cooler. (rad first, then tranny cooler, outside temps when driving usually dont go much below 60-70 degrees) were also thinking about the 2 quart extra finned pan. but first want to make sure the tranny can hold the power of the engine.
If I purchased a decent trans. cooler I would not run the trans. fluid through both, just throught the trans. cooler!
Running it through both would decrease your engine/radiater cooling capacity. With a bored block and stock radiator I would only use the trans. cooler for the trans. fluid. Not sure what temperature the trans. fluid should be, maybe 180 or so (I don't have a gauge on mine)?
that is very true, i wasnt even thinking of that. i am running it through an alluminum radiator, but overall cooler is better. maybe ill get a gauge for mine.
Over 700 hp for sure We run a Turbo 400 (built) behind a Stroked LT-1 with 19 lbs of boost in a 3800 lb car all day long (3400 stall)....not even a burp!! :TU:
