I know this thread is a little old, but this is right in line with my project and a couple questions i have. I will be installing a .460 lift cam in my 77Z and was worried I may have interference issues and need to shim. Any input would be great. I have a stock block with 82 NA flat top pistons and a P90 head. The reason behind the head was a turbo build that never happened, now im going with the Arizona Z 4bbl intake. I know the head is a little bigger (about 9cc's over the original) and im hoping the valves are gonna be up high enough to clear the pistons when full open. The other question I had was what is reusable in a cam swap, I have new rocker arms and see I will need springs, and was planning on new lash pads unless someone thinks otherwise. Lastly, has anyone used the MSA performance valve springs? they are only like 30.00 more then the Rebello outer springs for the inner and outer springs and retainers. I just want whats gonna be best for my Z, its been in build for 5 years, and as soon as the snow melts it will be on the road. Note: I will not be hard core racing, maybe a little track time and a pass or two at the strip, nothing above 6500 RPM.