Had a buddy give me a THM400 auto Chevy trans, I have a 350 SBC to mate it with, from what I read, it seems like the THM400 is not a good choice, anyone have an opinion? Building a 28 tudor sedan with a banjo rear and open driveline. Is anyone running a THM400 with their 350 in a model A?
Pile o shit I'll be by this weekend to pick it up. Are you kidding me? In my opinion it's the strongest trans ever made.
Well there are a Million street rods with them in em. Maybe not in front of a Banjo due to gear ratio but the tranny is not the problem. I think your friend was just trying to Screw you out of a Good gear box. I'd consider a different choice of rear axle before changing tran's. The Wizzard
Nothing at all wrong with the 400..I ran one in my old 33 Ford truck ( but it was actually a mutt...it was on a model A frame) for years and never had a single issue...I have one now in my 52 Chevy truck.. Many many people i know run them. and for a reason, they are a great transmission. About the only thing i hear people complain about is they take more hp to turn than a T350..BUT, the difference is like 10 hp or less and you'd never know the difference anyway..use it!
These boxes have been used variously by Rolls Royce and Jaguar over the years apart from all of the GM applications. I think that speaks for itself. Strong, reliable and smooth.
Been runnin a TH400 behind my 455 poncho for damn near 20 years. It's an 11.20 car with hundreds of passes on it...no tranny problems. dvz
THM 400 is a tough hombre, it is cheap to buy and cheap to rebuild. It is a big tranny, it will take quite a bit of more space than a THM350 or 700r4. These are big around the back of the pan. I had one in my 39, it was a bit of a challenge to fit into the modified stock X member which is not an issue on an A... (right?)
As mentioned, an excellent transmission. However, it may not be the best choice for your rod. They're a lot larger, heavier, and have higher parasitic losses than the TH350. With a 350 and a banjo rearend, the transmission isn't going to be your weak link anyway. I'm going to go against the flow and say that the TH350 would be the a better choice for your application. Bob
http://www.jalopyjournal.com/forum/showthread.php?t=228842&highlight=pontiac Have a look here, from 2007 if ya dont want it let me know, im in ohio and will have it out of your way in a flash
I have a turbo 400 behind my BBC and I run it hard and that trans hasn't missed a lick since day one.
http://www.jalopyjournal.com/forum/showthread.php?t=329266&highlight=dyno if you havent seen this one yet a th350 uses 36 hp and a th400 uses 44 hp
I would also have to say that the 400 is almost always overkill for any average application. The 350 is smaller, lighter and requires significantly less HP to operate. However they are plenty strong. Unless you have 1000hp or you are doing some serious off roading where you trans is taking a fair amount of abuse then a th350 should be fine. But if you already have a 400 then slap it in and abuse that mofo.
I just replaced the original 400 in my plow/tow rig after 230,000 hard miles! They are the most bullet proof automatic you will find! May be overkill for your application?
That is what I meant, wasn't sure if it was too much and more weight than I need to add. The banjo is of course the weak link, but love the look of it, if an old running flathead was affordable around here, I would have that in it, but the 350 is cheap and is a great motor for my use, I have my old 52 buick with the st8 keeping that one stock, I want to put some miles on the A sedan.
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