For my '70 Riviera, I am wondering if I would benefit from getting a higher stall converter? Under 10.1 compression, thinking of going with a Comp Cams 268 H cam. I read somewhere at one time that many stock converters that GM put in cars had a stall of 1200. Is that true? What works best for a big car?
I don't know about the big cars, but 72 skylark would foot stall at 1600 RPM. What the converter stalls at is a function of the vehicle weight, gear ratio, how much power you make, and the angle of the stator in the converter. So if you change any of these things it can affect the stall speed. The stock converters are pretty tight for racing, but work ok for mild build ups. The thing to consider is where the new camshaft is going to make power. Generally aftermarket cams boost power but also move up the range in which the engine makes power. So if you move the power band of the engine up high enough it is a good idea to change the stall to compensate. You want the stall speed to be higher than the lower end of the power range. There are trade-offs for bigger stall speeds. More heat (so use a good tranny cooler ), more converter slippage at cruising speeds, and more highway RPM for the same speed. All three of these down sides are related, more heat because the converter slips more, and more RPM for the same speed because the converter slips more. If you buy an expensive converter the down sides can be reduced. A little more converter will help acceleration. You just have to decide if it's worth the down sides.
