Oh, one other thought, I felt like some of the edges in the combustion chamber were really jagged and sharp. I wish I would have taken a flap disc or dremel and softened them up a tiny bit. I had 9.55:1 and I pinged a tiny bit on 87 octane and I think is was because of those sharp edges. The reason I passed on doing mine was because I did not have a way to measure the chamber volume and was scared I was going to mess it up. If I was in your shoes, I would borrow or buy a combustion chamber measuring tool and just, very subtly, round off the super sharp edges in the chamber.
79 Cherokee Chief (SOLD, goodbye old buddy)
(Cherokee Build Thread)
11 Nissan Pathfinder Silver Edition 4x4
09 Mazdaspeed3 Grand Touring
00 Baby Cherokee