i have a choice of using big valve ka or big valve c heads any difference between them. going on a 030 455 mild build. all info appreciated

 

As far as flow, they are about the same. If the K are 71 or newer, they will probably have harden seats,compared to the C.

 

K and KA heads are 1973-up, primarily for marine applications. Keep in mind that the seats are only induction hardened to a minor depth. Cutting the seats will pretty much remove the hardened layer.

 

rate the heads
pull off all the rocker arms
Lay your straight edge across the top of the valve stem
Any above or below is not ideal
Cheap leak down test
Put head in parts washer tank fill port with fluid
Tap the vave stem with a hammer "lightly"
Observe any leaky around valve face / head interface

I guess pick which pair will need less machining would be my choice these days

All The Best

 

 

thanks to all who replied good info and ideas