Max lift with stock valve length?

For example...

230seat/580open on a .660 net lift street roller cam (2.14I/1.81E, 1.5 rocker) 6500rpm max engine speed

280 seat/720 open on a .740 net lift endurance roller cam (2.20/1.81, 1.7 rocker) 7500rpm max engine speed

From this data you can see that increasing component mass (bigger valve etc), rpm and rocker ratio will necessitate an increase in valve spring psi requirements as well as attenuating service intervals.

A smaller diameter (wire), higher quality valve spring will help things tremendously by having less mass for a given spring rate. Isky, PAC, PSI, and Manley are good brands to investigate.

Use a +.50 lock in combination with a +.050 tool steel retainer to get 1.800IH and you will find that the LS and G3 Hemi spring offerings might work. The newer v8 engines use typically use 1.800-1.850IH springs which has opened up our short valve spring options.