I run a Sprock tri-z head on my 85YZ cylinder. Coolant hoses all fit perfect. I ordered YZ domes for the head and the one labeled "pump gas" has 230PSI I don't remember what the squish was but I run 110 with no issues. I've never even tried the "race gas" dome. I am using a YZ piston and matched the arch on the skirt to the cylinder and added the 2nd boost port. I've added the 2nd boost port to 3 different cylinders with no welding and never had an issue.