The wall behind (toward the plug) is about .400" away from the 1.94" valve on the 194 head, but about .600" (+.200" higher) for the same valve in a 292 head.
If the relief is contoured to the 292 distance toward the plug, and opened to the bore size at 90°, how bad is it?
For comparo, I made a .psd of the 2 heads, with a 3rd layer showing only the relief if anyone wants to take a look.
