I know the manual specs it out as .012 max, but the hot rod buildup was .018 and I have seen larger specs in other articles. Reason I ask is a I have a 72 455 that was a cheapo rebuild before I got it and one set (7and 8) specs out at .013 (tight) clearance....otherwise bottom end looks fine....I assume major concern here is oil (and pressure) loss from the rod bearings? later Tim
Tim, consider that rod side clearance as fixed orifice(s) in a flow stream- the larger the orifice the greater the flow rate. The increased flow will provide for cooler operating main and rod bearings at the expense of lower oil pressure as the flow rate approaches the oil pump capacity. In one instance, I ran across a set of Carillo rods in a BBB that measured .025" side clearance and required the HV pump to survive. Also consider any excess oil that will tend to wrap around the rotating assembly at RPM, making a crank scraper a must. I would recommend sticking close to Buick's max clearance unless you are considering some excessive bearing loads (hi compression, nitrous,100%+VE,ect) then you may consider opening the clearance up a tad. Good luck!
I understand the theory but was more or less curious on what you could get away with on the BBB. I didnt thnik .001 over the limit would matter much, but you never know, thus the question. thanks Tim
