77 360 vs 86 360
Isn't an '86 a roller engine?
That would sew it up for me.
Heads are better, cam being a roller is a winner and the profiles can be custom ordered with a quick phone call and at no extra charge or a minor amount more at worst.
A head milling would improve the ratio quick and easy.
New heads, like the Indy X head would be a serious homerun!