I just installed a 700R4 I purchased a few months ago. It was rebuilt 3 yrs ago by prev owner w/ a shift improver kit (probably a B&M), vette servo, bigger pump, and bigger input shaft. All this is what the guy told me. I installed it with the stock torque converter. It came out of an '85 IROC.

Now, my motor is a '73 400 w/ stock heads (#997 casting), performer intake, performer 750 carb, either a C.C. 268H or 270 magnum cam, magnum 1.52 rockers, HEI, tri-y hedders w/ 2 1/2" pipes to X pipe to dual Thrush turbo mufflers, 3.42 posi rear, 28" rear tires.

I am assuming the block was never bored over, just has a stock rebuild, assuming no port work to heads, and also assuming cam specs.. (Cam has lopey idle, but not radical).

According to Engine Analyzer 3.0, this motor makes pk HP of 277 @ 4,000 RPMs, and PK TQ of 373 @ 3500 RPMs.

Now considering that 90% of my driving will be at or below 3,000 rpms b/c of the OD, that puts the power the trans will see at:
TQ = 363 ft-lbs
HP = 208

I know this isnt a tremendous amount, but I am concerned as to if/how long the tranny will last behind my motor..

Should I upgrade to a better converter? Will this relieve some stress off of the tranny? I dont have the money for a rebuild now, as to I just spent a ton on the tranny, install, tc lock up kit, tv adapter kit, shifter & other work to car. But I am just looking for some reassurance that it may be ok if I dont beat the hell out of it. I know that the reputation of this trans isnt great, and I also read somewhere that a stock unit can only handle like 360 ft-lb of TQ b4 the sun gear shell blows.. How true is this?

Thanks in Advance for any advice n tips anyone might be able to offer...

p.s. I got the tcc lockup and tv kit from bowtie overdrives.. They have a 2000 stall converter for like $149.. think it is junk??

Thanks
Joe

 

I wouldn't worry about it. The tranny's are quite strong for street driving. Drag Racing is about the only thing that will kill them. The stock torque converter is fine. In fact, much better than " Fin basher " el-cheapo converters for $149. I would avoid converters like that at all costs. Quality convertors are not cheap. Ya get what ya pay for.

If you really want to extend the life of the tranny. Go buy the biggest aftermarket tranny cooler that you can and plumb it in series with your stock tranny cooler in the rad. The install a full Synthetic transmission fluid. Amsoil makes some excellant products.

Then drive the thing and enjoy.

EDIT: If it makes you feel any better, my buddy has a 1980 Trans-Am with a 462 CI Poncho. Over 500 hp and 550ft\lbs of torque. He autocrosses and Hillclimbs. 315\35x17" tires. 700R4 with some mild mods ( Transgo kit, 9 disc clutch pack, HD Diode over-running clutch )....has had it in about 5 years. No problems at all.

 

All the above being said....I just noted that the tranny came out of a 1985 IROC.

The early transmission had several problems. All of these were fixed by about 1989. Weakest points in early models were: Overrunning clutch, Front pump ( Pump vanes not hardened and small drain back holes) and weak planetary gear set.

Sounds like the front pump has been up graded. That leaves the planetary gearset and over-running clutch. Can you phone the builder about these? If that is not possible then I wouldn't worry about it....unless you beat on it hard. If you Drag Race then the first things to fail will probably be the Planetary gear set ( if it was the early one ) or over running clutch