If you already have intake valve reliefs in the pistons, the biggest reason for an angle mill is gone (preventing the valve from hitting).
The compression increase from an angle mill is always less than a straight mill to the same distance.
The head's width prevents a high angle cut, because it will take too much off the deep (plug) side before sparking out on the shallow (port) side. This means that the new angle won' improve the ports efficiency (something you might get with a V8 head).
