What type of 400 to look for?

[walkerb]

I got my 454 030 over back and she's sweet. When I get it together shell be dyno'd and be around 400hp? Got a sweet deal on worked over iron heads too.

My question is my 2wd 75 shortbox stepside has a turbo 350 that I know Im going to gernade pretty quick. Im going to start looking for a 400 and Im not sure what to be looking for so I can still use my stock drive shaft and my 12bolt.

I know the tails are the question. Just not sure really what I need. Thanks

[68Timber]

The TH350 will hold 400 hp easily.

[RaysK20]

For the cost of the 400 swap, you can add a few items to the 350 and it will be fine. Unless your planning slicks and drag strip times. I tormented a th350 behind a spicy 396 in a 71 camaro for several years. Never roasted the trans but it ate two 10 bolt rear ends.

[walkerb]

Originally Posted by BRUISER

The TH350 will hold 400 hp easily.

You think? I did have it built 5-6yrs ago and cant remember what stall we went with.

The dude that the Machine shop that built it for me did suggest that withe the ca that I look into getting one.

[walkerb]

Originally Posted by RaysK20

For the cost of the 400 swap, you can add a few items to the 350 and it will be fine. Unless your planning slicks and drag strip times. I tormented a th350 behind a spicy 396 in a 71 camaro for several years. Never roasted the trans but it ate two 10 bolt rear ends.

Maybe I'll just run it untill she breaks.

If I did want to swap it for the 400 what 400 would fit my truck? thanks

[RaysK20]

The 400 will bolt in. You will need to move your crossmember back though. Also you will need to have your driveline shortened with a different yoke. The 400 uses a electric kickdown switch so that will need to be found. You would gain some strength, but the 400 is power hungry and will use more horsepower to spin it. For the cost of a 400 and the mods to get it in you can really beef your current trans. My vote goes for running the th350.

[Seven9er]

I went from a 350 longtail to a 400. I had to move the cross member back and get the one piece DS lengthened 3 3/4". I was told the kickdown goes off vacuum???? hence the vacuum modulator...... Im running a 2200 stall in mine but I wasnt able to see how it was because the pump ate itself before anything an I didnt move at all. there is one connector on the side of the trans but I have no idea what its for so that may be the kickdown.

[spinem]

lmao! 350 holding 400hp lmao, naaa man. ill bet money on it making noises and contaminating ur water supply.

If ur gonna drop money on a 400, just put in a 700r4, or a nice and new 480lE

[68Timber]

Originally Posted by spinem

lmao! 350 holding 400hp lmao, naaa man. ill bet money on it making noises and contaminating ur water supply.

If ur gonna drop money on a 400, just put in a 700r4, or a nice and new 480lE

lmao! 700R4 over a TH350 in a durability comparison? lmao!

[D-Day]

4L80E would be king, especially one from Hughes. The rock solid stability of a TH400, with 700R4 overdrive goodness. Tow, drag, or cruise, 4L80E would be perfect. Would like to put one in my truck one day...for now, I have a 700R4 since my engine is, for all intensive purposes, stock power. I don't trust 700R4's for hard use, though.

[cableguy0]

A th350 with a heavy sprag and drum assembly,good shift kit and a good converter will hold 400hp with no issues. A 700r4 is just straight not a good choice unless you want to spend A LOT of money and do a lot of praying. the th400 is a good option but as mentioned you gotta change a few things. Its probably best to just use your th350 and see what happens.

[slugish]

Iwas told by more than one trans . guy that a 400 would be stronger but would lose some hp & torque compared to a 350 . 450-500&up hp yea a 400 would hold up better. Just what Ive heard thru the years