360 engine build opinions - first engine build

The idea is to smooth out any ruff edges or sharp edges to prevent hot spots that my casue pre-ignition.

You'll also might want to look into thermo coatings on the piston tops (Crown) and cylinder head chamber.

P.S. I'd go for the bigger cam myself and use a slightly thicker gasket. Just don't loose the quench effect. It is important in this type of set up.
If, IMO, you use the thermo coatings on the piston and cyl. head chamber, you might, MIGHT very well get away with 87. Otherwise, you'll need 89. And have the timing set to where you want it.

Do not retard timing to suite octane goals. This is a big power robber!!!!