It depends on alot of varies..Compression is a big factor...I run a 572 bbc with a Holley that was modified to reach 1500 cfm on the flow bench.I can change the oil,and after a couple of runs,the oil will thin and smell of race fuel....I change it regularly...It is a sacrifice...Ya wanna go fast,Ya pay...Ya might also check the rings with a leekdown test...Good Luck!!!!! dan