How does overlap come into the equation?
I always noticed that Delta cam grinds have significantly less overlap, but more valve lift compared to stock Chevy and McGurk cam grinds.
Delta's 254 adv. duration single-pattern grind has IO 4.4 BTC and EC 4.4 ATC timing events.
The popular 'Bulldog' 254/264 dual-pattern grind has even less overlap at IO 2.7 BTC and EC 2.7 ATC.
I don't know what overlap they use on their longer duration race grinds, but it may not differ much.
I wonder why Delta uses less overlap and single-pattern cams compared to the supposedly tried-and-true McGurk dual-pattern approach. They apparently ignore this theory.
Did Delta learn from the decades of grinding cams for these engines and get better performance?
Or is Delta's approach simply more tailored for street engines without lopey idle, which may be their largest customer base for early Chevy 6?
