Good video by @318willrun

Dartfreak has it correctly. You see, I already had 360 heads which is a .4 deduction from stock 318 heads, so I only have to subtract .4 tenths more which is exactly what dartfreak just quoted in post 107 in which is probably really really close. My butt dyno says it's high 12's. 4 tenths would be a 12.9.
Hot dang I'm getting good at this stuff! Haha