It seems this car might turn into a track car, and I know the 6 speed wont last, so was thinking of going to a auto. Not sure which one to get though. Don't know what converter to run either. This is what the car has.

396 Solid roller
cam-250/256---640/614 lift 112ls
21.5.1 compression
AFR210's ported by GTP
150-200 shot on top of that.
Currie 9"

What would you guy's go with. What will hold up to the power(750rwhp on spray depending on the shot)
What converter might you recomend?

 

TH400, I bought mine from Rossler transmissions at http://www.rosslertrans.com/ and got a converter from Coan at http://www.coanracing.com/

Rich Krause

 

Thanks Rich.

I heard running the th400 eats up alot of power. Any truth to that? Is that trans simular to the ford's C4? I would like to shift it like the C4.

 

I just converted from a M6 to Turbo 400. I have a stock engine. I lost .3 and 5mph. The Turbo 400 that I have is a "full race" and will take 900+hp. Leaves a lot of room for next years engine upgrades.

 

It not the TH400 per se, it's the converter primarily. I am sure that there are some small differences in the amount of hp eaten up by the different automatic trannys, but most of the difference in rwhp between an auto and a manual is in the converter. Most cars lose between 5-8% rwhp when switching from a manual to an automatic. For relatively underpowered cars, they will run slower. For a powerful car, they will run faster in spite of the power loss. The reasons? Better launch, torque multiplication and no interuption in power between shifts (if you don't powershift your manual). A stock A4 is quite a bit more efficient than a race auto because the converter is much "tighter". Also, the A4 will lock up in 4th gear (though this doesn't happen at the track). When the converter is locked, I believe that an automatic is as efficient as a manual.

Rich Krause

 

If you're looking to put a lot of power to the ground, the 400 would be the best route. I had mine built locally for $1K w/ a brake. You'll also need the dipstick from Madman, different torque arm mount(mount to the frame), M6 x-member, 153-tooth flywheel, different slip yoke for the driveshaft, the GM reluctor from Dal, and your computer programmed to delete the A4 commands.

 

I've already got a heavy duty torque arm from BMR.

Why would I need my computer programmed? It's a M6. If I stick a TH400 in that I shift, just like the (ford's)C4, I should be ok right???? If I'm wrong please let me know. I really don't want to go this route, but I know the 6 speed wont last.

 

th400 all the way. I got mine from www.dynamicconverters.com
Later
Matt

 

My vote is for either a th400..if you have limited weight reduction. Or a Powerglide if your 3000#'s or less.

I dropped a glide in last year (had a t56)...WHAT A DIFFERENCE!!

 

The M6 crossmemeber is too low remember when and if using it. I made a crossmemeber out of alum and mounted it, the trany sat about 1" back too far and roughly 1.75" too high for the m6 trany crossmember

I choose a turbo 400. Talked to them about the diff in power loss from the 350-400 and they said you can make a 350 strong and more hp transfer but they still said go with the 400.

Steven

 

I would have to say Rossler Turbo 400 with the Rosslock Transbrake. I love the tranny. If you dont eant to take my word for it check this site www.gofastzone.com and four other guy's on this board run his tranny also. I figure if the tranny will go more than two years behind a 1800hp 3,000lb. doorslamers then it will more than fine for anything a LT1/LT4/LS1/LS4 can dishout!

If you go with a Coan converter, a peice of advice would be to spend the extra money and have Coan build you a costume converter to your setup. Other than that I would never buy one of his shelf converters. I have had my share of broken Coan tranny's and converters. The one thing that didn't give me any problems was the costume converter he built for me but then again for $1200 plus it shouldn't! I'm looking into a NEAL CHANCE converter. I have heard nothing but great things about the converter and the company. I know two other guys that own his bolt together and both guys said they would never go back to a Coan unless it was their only other choice.

 

It's funny, but I ended up with exactly the same combo (Rossler TH400 with his brake and a Coan). I strongly considered the Chance converter, but at nearly $1,700 it made the ~$1,100 for the custom Coan look like some sort of a bargain. Rossler actually recommended Coan, and that meant a lot to me.

Rich Krause

 

i'd be more worried about what kinda fuel you're going to run with compression like that

 

Diesel

Even an alcohol engine doesn't need much more than 15:1

 

lol... ..I wasn't going to say anything about that compression ,but I thought it was kinda funny too. I'm sure its 12.5.1..anyway..if you are concered about weight ,go with a TH350. There are plenty of them out here running in low 9 to high 8 second machines. But if you really want the bullet proof set up ,go with the TH400. Just my $.02