So if you run serious boost, you need to switch to a mechanical roller then? Not necessarily but wouldn't hurt depending on what you consider serious boost. Still don't understand how increased manifold pressure holds an intake valve open. I might be way off the mark here, but the way I think it works is: boost and valve surface area = extra pressure required. So 10 psi on the back of a 2.02" (pi x r squared) valve would require a valve spring with (roughly) 31lb more seat pressure than it's N/A counter part to work the same ?
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge.
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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