I recently purchased a old school built in 74 340, and not ran since. Trw full domes, crane r280/427, 108. Mopar part number P3690795 Solid roller, block is o ringed. Etc etc, It’s a killer old school build. Anyhow does anyone know what the spring is that cam calls for pressure wise? I can’t find any info. The box of springs that came with it and was ran in the garage only says 475 on the paper work. Unfortunately it’s a cast core it looks like....