It'll be OK

That cam and compression are nearly spot on for a stock 390 GT. I seriously doubt any piston to valve clearance issues - but I always tell people to check.

I don't think the DCR calculators are all that useful in mild builds. They're mathematically derived values that are neither dynamic nor a ratio - - the numbers are really experientally based comparatives only. The original intent was to illustrate how much compression you could "get away with" by using a big cam. Going the other way (little cam, modest compression) tends to give funky numbers that would lead you to believe that any stock engine will detonate like crazy..

Barry Rabotnick
Survivalmotorsports.com