Compresion on a stock 70 mid 70's motor (which likely most of us run) at around 8:1 compression should be bumped up no higher than 9.5:1, which is still ok with 87 Octane gas. You will of course need to make SURE of what pistons are in there to make sure they aren't bumping the compression up already.
The springs are "weak" comparatively, but unless you run a high RPM motor, lift over .475 is not necessary. (I know someone that was running .495 lift on the stock vortecsprings/studs for awhile) I've actually heard .450 lift is max on stock springs, but close enough..I will be running .452 max lif on the stock springst, because I want the low end grunt. In any case, the pre-assembled vortecs have press in studs, which are not conducive to longevity with a high lift cam. They take self aligning (rail) rockers. Comp Cams makes the Steel Pro Magnum Full Roller Rockers for the vortec heads, so finding rockers is not a problem. Intake manifolds as yet from Edelbrock, are Performer in Spread and Square bore combined, RPM in squarebore only..so no quadrajet on high RPM manifolds.
The heads have no exhaust crossovers, so no choke/carb heating on the Edelbrock Performer intake..Performer RPM yes, you can run water under the carb from an auxiallary fitting. Intake does not have provisions for the choke coil like most pre-electric choke chevs, so manual, draw through or electric choke is necessary.
Exhaust mounting is the same supposedly.
Dorian
My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>