The original 1.76 powerglide planetary gear was only designed for 400 or so horsepower. So keeping that in mind, we have had 3300 – 3400 lbs cars go in the 8.50s – 8.60s with stock 1.76 planetaries. What we have learned is that some sets are better then others; it’s like some batches had better steel or better heat treat, I am not sure. What I do know is when you reach a certain point, the stock OEM 1.76 is a time bomb. The question is not if it will break, it is how long till it breaks! The answer is anything beyond about 800 – 900 HP we need an aftermarket gear set. A set with big straight cut teeth and a forged output shaft carrier. Don’t buy the cheapest set you can find. The cheaper ones will pit and wear out way too soon. Buy a high quality set and you will be glad you did.
You can also email Mike Stewart at email@example.com