Since I'm addicted to my B&M ratchet shifter, the tranny in my '86 IROC is going to see a very short life and will need rebuilt soon . I want the rebuilt version to be rock-solid. I could always put a TH-400 in, but I'll lose my OD. Can my '86 TH-700 be built up to be almost as tough as a 400, or should I use a 1987-later TH-700 for the project?

I'll be in no way producing enough power to even warrant using a TH-400, but it's always nice to know that I'll have a strong, solid tranny that can take a beating.

 

The 700R4 can be setup to take about 500-550 horsepower maximum without some major modifications. You will need the 9.5" torque converter from A.C.T. or the Vigilante to get it to take this kind of HP & live. With the stock 12" of any stall will start to break parts when you get near 450 HP. Let me know what you are doing to the motor and what gears are in the rear end, and the type of driving you are planning on doing.

 

hey pro built, what kind of torque numbers would those HP values coorespond to?

 

Well right now, my 305 TPI engine is basically stock... I'm supposed to produce 190hp and 285tq (I haven't actually dynoed it, though). I'm still unsure as to what I'm going to do with the motor... I may upgrade it as far as I can go with a 305, or I might convert over to a 350. I may even be looking at a ZZ4 setup if I can figure out a way around emissions. I don't really see the car producing any more than 400 horsepower (that's what my '67 SS is for ).

The car has 3.23's in the back but I plan on moving up to 4.10. Since I have overdrive, I don't really think that the higher gearing in the back will matter all that much for highway driving. The rear end will probably be rebuilt because I'm slowly losing my posi.

I am undoubtedly going to get the transmission rebuilt just to ensure that I'll have trouble-free operation (it only has 68,000 miles on it, but I'd like to be on the safe side). Not sure if I'm going to do it myself or have it done. I also plan on getting a higher-RPM torque converter. The tranny mount needs replaced because the driveshaft was scuffing the underside of the car a little bit; I'll be replacing that in a few days.

I'm not particularly hard on the car, but I'm not gentle with it either. I find myself often banging through the gears (in talking with a tranny specialist, he said that shifting an auto really doesn't do anything to harm the transmission -- apparently the pressure equalizes or something?). I'll be taking it to the track at least once a month... and of course I'll be doing some stoplight racing.

In regard to my rebuilding, would it be wise to stick with my pre-87 700 or move ahead a few years?