Th350 Vs. Th400

[SAVANNAHAUTOAIR]

I realize many high HP guys are using 400's because of their strength and design. However, they weigh a ton, and it seems a built 350, which is lighter, could hold up fairly well.

My question is, have there been any testing as to how a 350 holds up? Let's hear from you guys who are running one. It seems like a good choice, as it is much lighter.

Also, what is the first gear ratio of a typical 400 vs. 350 vs. 2004r?

Thanks,
Brett

 

[GNeric]

I've built quite a few 350's and used some good parts (34 element sprag, hardened outer race, late 700 rear planet) and they hold up pretty darn well. One was built back in '90 for a 454 73 Camaro and the guy barely serviced it last month. Found a little black "fuzz" on the magnet but still had cherry red fluid.

The first gear ratios you are looking for are:
TH400: 2.48
TH350: 2.52
200-4R: 2.74

 

[jakeshoe]

A Th400 is not that much heavier than a Th350.. maybe 15-20 lbs...

 

[GNeric]

I'm sorry, I meant to say late 700 rear one-way clutch. Planets are different.

 

[turbocliff]

I too would recommend the TH350 vs. a TH400 in a full weight GN running as quick as low 10s. I bought a TCI TH350 Streetfighter trans BOP bolt pattern, with a TCI 4000 stall for my WE4 car three years ago. I parted that car out, but kept the trans which is now in my 87 GN. Between the two cars, this trans has only about 3000 miles on it, but about 25 mid-high 10 second passes, and prolly 100 low 11 second passes. No problems ever. Still shifts as hard as the day 1 got it. Also, not sure of the actual 1st and second gear ratios, but I believe that this trans is more more efficient on a low-rpm motor like most GNs. Lauching off the foot brake, I shaved usually a minimum of .15 sec. off my 60' times going from a 200r4 to the TCI trans, with same rpm and boost level launches. Also, always have managed better ET/mph vs. the 200R4 with various torque converters.

My Trans is for sale too! But thats only because my new combo I hope to be pushing alot more than the 460Rwhp that the car had last year.

Cliff