I was talking to Transmission specialties today about running a TH350/TH400 in my car and we went over ALOT of info.I was always under the impression u would wanna leave the line at peak TQ and I got this reply----->NO NO NO from the tranny tech.

He said u wanna be (DRAG RACE) more into HP when leaving the line which blew me away.He said after your 1st shift your gonna wanna stay there and beyond all the way down the 1/4. (6600 shift down to 5700 threw the gears)

We discussed what he thought would work for me and I told him I still wanna drive the car alittle bit.Well after giving him weight,**** points,dyno info,peak numbers,old ets and tranny combo I have now along with gearing and tire size he suggested 1st to send him the dyno sheet (I live by TS so I can show him it) and he thought something in the 4500 to 5000 range was what I should be running in my car.

He also told me a 2.75 1st gear in a 3500lb car would help ALOT.He said I might wanna consider a 3.90 gear instead of the 4.10 with the 26in Slick but to try it first and see how it works.He also told me I WILL PICK UP ET for sure over the foot braked 4200 VIG/4L60E I have now.

Sound about right for my radical H/C setup?
(6300 PEAK HP/4500 PEAK TQ)(Shift at 6600)

JS
Wanting a TH350

 

If you go with the smaller TH350 tranny, make damn sure its upgraded to run with a heavier car. I agree with running a 3.90 gear with a 26inch slick. But why run a 26" slick?? Run a 28" Hoosier or Mickey.

I take it you want a transbrake setup. You will love it, and it will pick up ET above and beyond footbraking a 4L60E, not to mention an M6 with a similar setup.

PM if you need a parts list, because there are ALLOT of freaking parts to buy above and beyond the transmission.

 

Nothing wrong with running a converter a little on the loose side, espacialy if you are lacking a little on the bottom and can pull some high RPM. I think a 3.90 with 26" tall tires will be right on the edge though depending on what RPM you are willing to pull to, remember to take 5-700rpm converter slip into your calculations..

I have a lockup TH350 with a TP4200 converter and it seems like a great combo. I have a 2.75 1st gear and the bigger intermediate sprag/direct drum and it shifts great. I have been beating on it pretty hard and its still shifting fine but until it dries out a little here I wont be able to take it to the track and see what it 60's. I am going to start with 3.70s and have 27" tires but I'm not sure if I'll make it with the 3.70s. With the 3.42 I am at 6000rpm at 122mph so its going to be close with the 3.70s..

Its kind of hard to lose the 3.06 1st gear and the OD on a 4L60 but this trans is light, easy to rebuild and hopefully will hold up a while, we'll see...

 

I wanna cross threw the lights at 6600 so I think a 3.90/26 should work fine.
But since I have 4.10's I think a 28 might be the way to go?

 

why not stick with the 28" tire? hook better at a higher more stable psi? esp since you already have the gearing.

 

I would just run the 28's.

If you are making it through with a 3800vig without locking it you should be OK with the 28"/4.10 and a little looser converter - one way to find out..

 

3800 Vig is more like a 4200 flash and that was on 26in tires..
I believe a 4400/28 and a 4.10 will be wicked..

 

how are these trannies on the highway with normal crusing?

just wondering
thanks
ed
firebird455@onebox.com