Reply to "Please help a beginner ☺ with Valve Spring Questions"

The 351C is equipped with a “big block” style valve train, meaning large (heavy) valves, large (1.5” diameter) valve springs, high ratio rocker arms, sturdy push rods, and sturdy (thick walled) tappets. Valve springs for flat tappet camshaft applications should have 115 to 130 pounds seated force and 300 to 330 pounds force at maximum lift (over-the-nose). Valve springs for roller tappet camshaft applications should have 150 to 160 pounds seated force and 370 to 400 pounds force at maximum lift. As a generalization valve springs for the 351C are sourced from valve springs designed for the big block Chevy. However, be aware that the installed height of a 351C valve spring is shorter (1.82”) than the installed height of a BBC spring. Shortening the installed height of a valve spring increases the seated force and shortens the spring’s maximum lift spec. The maximum lift should not exceed the valve spring’s “coil bind height” + 0.100”. The installed height of a spring can be increased by fly-cutting the spring seats or by installing valves with 0.100” longer stems. Longer valves impact rocker arm geometry however (as do higher lift camshafts).

I've been working on the following flat tappet valve spring chart, but its incomplete. The info in red has not been verified, and there is one blank field too.