yo, What needs to be done to them to support 400-500rwhp (I've heard the mods aren't all that substancial as they are already fairly strong?) and what would it cost me roughly to turn up to a transmission builder with a TH400 and get it built to those specs? I'm currently turbocharging my VR Senator 185i and somehow I don't think the shiftkitted, corvette servo'd turbo 700 will hold up so I'll be looking at this conversion in the near future. What problems will I run into installing the turbo 400, I understand I will need a custom tailshaft, shifter and converter (heard the flexplates are the same?) but will the speedo cable be compatible? Also it would be a full manual box, does this mean I will need a manual ecu? cheers brad

Free bump! I'm looking for the same kind of answers for the t400 I've just put behind my stroker in my vn. Any help would b great. Cheers. Lucas

I paid $2600 to have a T400 built for the LS1. Not including supply of box, not including converter. Do yourself a favour and track down an Australian case. Apparently they are stronger/thicker than the U.S. ones. I has a mate split his U.S. case and destroyed the box. You will need a manual tune to run it as there are no electronics in it at all. Very simple and strong boxes as long as you don't mind only 3 gears. Tailshaft will definitely be so different as the box is different length. Converter - not sure, I got mine built custom at 4800 rpm anyway. Speedo cable - not sure of difference as again I got custom made one to suit. ---------- Post added 05-10-12 at 07:14 ---------- P.s. for the flex plate - do yourself a favour and spend $250 on a new TCI one. If your putting some power through it, last thing you want is flex plate coming apart. ---------- Post added 05-10-12 at 07:14 ---------- P.s. for the flex plate - do yourself a favour and spend $250 on a new TCI one. If your putting some power through it, last thing you want is flex plate coming apart.

It would need, full rebuild, extra clutches in the clutch packs, commercial direct drum with 34 element sprag, roller bearing behind pump and competition thrust kit, full manual valve body, pressure reg spring, lube and oil flow modifications, alluminium sump. You would get away with standard input and intermediate shafts.

im using a stock, modified manual valve body. same build by the shop im using is holding 620rwhp in my mates vl v8 turbo no dramas, he harsh on it too. just gotta keep em cool mate. obviously if your building one, then get it built right. but i just went for a quick wreckers special and got the manualised and afew little things, they can hold them quite well. aZ` off here had a nice basic one in his and held 400rwkw+. Steve

Quote: Originally Posted by cookie747 [View Post] It would need, full rebuild, extra clutches in the clutch packs, commercial direct drum with 34 element sprag, roller bearing behind pump and competition thrust kit, full manual valve body, pressure reg spring, lube and oil flow modifications, alluminium sump. You would get away with standard input and intermediate shafts. im no expert, but looking at the power the OP is looking to make, some of those mods wont be required. fair sure the 400's in standard form are rated at around 450rwhp, depending on age/condition etc. edit, and if OP's engine is standards, will more than likelly make 400ish hp rather than 500rwhp