Thanks. Moving on to the cylinder heads -after taking a bunch of measurements and some quick mock-ups it looks like cracked Magnum heads will be employed with G3 Hemi valves, springs and locks. I have some 5/16 x 3/8" Oldsmobile studs from Comp cams and will use them with Comp's 4825 guide plate and some Chev stamped steel rockers from Melling. I'm backing off on the idea of a roller rocker ATM in order to keep this as cheap as possible. The springs will provide 118 lbs @ 1.700 I.H. and 290 lbs @ 1.200". Pulling the cages off of them gave me the rates I wanted. This valvetrain should be lighter than even the stock Magnum stuff--I'm hoping it will turn the RPM I need. J.Rob