[W2zero]

DM
He's right about the only obvious difference being the firing order. Most of the rest of the differences involve pulling parts off or getting a bore scope. The 86 HO had the infamous E6SE high swirl heads. Small valves and heavily shrouded intake with forged flat top pistons and the tiniest of valve reliefs, just a nick or two really. What a lot of people are passing off as an HO roller cam motor are the generic roller motors with the E5AE cams and E6SE heads with cast flat top pistons. All HO motors from 87 up have the E7TE truck heads. You can see the number with a mirror with the intake off. I am playing with one of the generic motors and bolting home-ported GT40-P heads on with backyard valve reliefs.

Craig