I will talk to my machine shop about machining the intake side, it's a better idea than milling the actual intake. But I have had some open chamber 273 heads milled a whole 60thou to increase the CR and don't need to mill the other surface. Just put a rat tail file through the intake holes and slightly open them up a bit and use RTV Gasket Maker instead of the front and rear intake wave seals. (It is a low 8.4:1 engine and using the original in-the-hole stock pistons) Which I'm glad about because it cost me A$200 each head to do that. But it was a low mile engine, never been pulled down so everything was almost like new inside. Just needed a hone and refit the original pistons
