intake needs cutting how to measure

ok guys bob got the low buck motor done now I need to know how to measure the intake to be cut to fit the heads????.the heads im sure has been cut but how much I have no idea so I need to find out what needs to come off the heads to finish that up..

I read to bolt the intake to 1 side of the head and measure from there with a gasket of the thickness I plan to use..anybody use this way or try it????any help would be great..