[blueghoast]

Originally Posted by mgarblik

I hate to see Tom and Ed argue over this one. Hard data, that I can quantify and look at on a spread sheet or something, I just don't have. Ed, I don't know if you read the six part article Tom posted but there was some good info in there and very similar to what I read in the Sunnen engine rebuilding text book by John G Edwards, 1998. General "rule of thumb" for the past 30-40 years is high stress, high RPM V-8 engines without support for the main caps will benefit from some overbalance. BBC, and Pontiac fit that category. The question that is never really answered is how much? I have never heard of an overbalance greater than 5%. Seems like 1-2% is typical and the 4% we used I just tried because we were killing main bearings. Turns out that was not the issue but I never went back to 2%. We just left it when the bearing issue was corrected. I can't say I have ever heard of a situation where a slight overbalance hurt anything. The gains are all in bearing life, not HP IMO. So if you have zero bearing issues, I would keep doing what your doing or maybe try 1, 1.5%. Engine balance even in 2020, is still a bit of black magic I guess.

So what was your issue with killing the bearings if I might ask. Thanks

GT.