Why on earth are the big block aftermarket head valve cover bolt hole locations not standardized? You can see that between the EZ Heads and the TF270 there is a 0.070" difference in one set of holes! That's crazy! WTH?

These are actual numbers from the manufacturers (I have verified 2 of the 3 and the 3rd looks to be accurate also). I would like to thank each vendor for providing the information - it helped me a lot in getting my valve covers to fit.

So ever wonder why valve cover bolt holes are so big?

Attached PDF document
holes.pdf (82 downloads)
67 Coronet 500 9.610 @ 139.20 mph
67 Coronet 500 (street car) 14.82 @ 94 mph
69 GTX (clone) - build in progress......