428 Rotating Assy.?

[Anthony]

Originally Posted by olddog

My memory (that I do not trust) is that the larger valves for the 427 will hit the cylinder wall on the smaller bore 428. It seems that the cylinder can be machined for the valve to clear, but it is argued that the shrouding of the valve makes it not worth the effort. I'm not sure if the 2.19" works OK with a 428 or not. Hopefully someone will let you know if I remember this correctly or if I'm full of crap.

Genuine ford 427 heads have a wider spacing of the valves than 390-428 heads, both the intake valve and exhaust valve from bore centerline. I think you can run 427 heads with 2.19 valves with 4.13 bores, but you can't run the 427 TP heads with 2.25 intake.

The edelbrock heads from what I remember, have the intake valve spaced from bore centerline like a 428 head, and the exhaust valve spaced like a 427 head, for both of their FE offerings, the 428 and the 427 head, mainly different in the combustion chamber size and exhaust bolt pattern, but again, no difference in valve spacing, so running an edelbrock 427 head on a 4.13 (4.160) bore block should be OK.

The other significant factor concerning this is proper rocker arm spacing on the shaft to get the rocker tip on the center of the valve stem, as again, the edelbrock head is neither an exact 428 or 427 head, but a mixture of both.