I know flow number aren't everything, got any ideas why these LS heads can make well over 500 hp with mild ish cams and low cr with these heads that really don't flow overly well, for the power they get from a basic cam swap?
I’ve had this thought for a while. I think it’s the ports. I bet if you analyzed one of those ports you’d find it has good speed and port energy. Plus the combustion chamber is 40 years advanced vs our old iron heads.
And they respond to cam swaps well because the factory cams are tiny! On non HP engines, they have duration in the 190’s @ 0.050. Lift is around the .470’s which ain’t too bad, but either way. They’re baby cams.
Put a good head on one of our dinosaur engines and watch it come close to an LS engine. It’s been done here:
Wouldn’t be surprised if adding 1.7 rockers and using a roller cam on that same engine would put it within spitting distance of a 5.3 with a similar sized cam and compression.