DUH!!!!!!

How many times do we have to go over this?

In the late run of 383s, they used a cast crank with external balance. When the 400 came out, the cast crank versions used THE EXACT SAME CRANK AND EXTERNAL BALANCERS. Meaning that what was attached to each crank was THE SAME.

The same thing happened with forged cranks. The EXACT SAME CRANK went into forged crank 383s and 400s. Chrysler kept piston weights the same to allow them to do these kind of swaps. Shoot, when the 273 came out it had a special thickwall pin so they could use the same crank as the poly 318s. Chrysler was a company that was strong on engineering and that means they were very good at figuring out what they could get away with.

Plus, the factory balance jobs were nowhere near as accurate as people think is necessary nowadays. AND, people who bought Mopars didn't flood the dealerships with complaints about the engine vibrating.

All of this "you have to balance because there's an 11 gram difference in piston weight" horsepoop is just that.....horse poop.

Now I agree that perfection is better than nonperfection. But how much money is it worth?

There is a board member who I respect as having raced a lot of smallblocks who replaced his factory 318 pistons, 591 grams, with KB 167s, 507 grams, and ran the engine and he claims it didn't run any rougher. I believe him.

Ever hear of overbalancing? Underbalancing? They do it on purpose to race engines. What we think of as God's truth about balancing a V8 is mostly what was figured out to work about as well as it could work. It is empirically driven, not deriveable from mathematics.

For one thing, piston motion is NOT a perfect sine wave.

R.

Chew on that!