12g940 head

[Rust bucket]

Hi all, got myself a 12g940 head today from an 1974 Marina i'm told, somebody in the past has had the same idea about useing it on a small block engine because one of the exhaust valve seats has already been recest a little to far it looks to me.

The distance between the head face and the valve is 11.2mm, the other three are 8.2mm, would 11.2mm be ok?.

[linearaudio]

11.2mm would be fine(almost too much!), anything over the magical 7.8mm figure will be good. Only thing to check is the radius from the seat to the manifold face, it can get a bit dis-advantageous unless the "short" side of the tract has been smoothed, but it is all relative- in the worst flowing case it will still outflow a stage 3 1098 head for much less outlay!

[bmcecosse]

11.2mm IS FAR TOO MUCH........ that's serious recession......you would need to put a seat in that one to use it. The others at 8mm are perfect - use them as they are......