Sailor Bob

Just went through a significant amount of trouble to locate and drag home f54 with a P90 head - was gonna go turbo, but there was too many expences. I have a set of rebuilt SUs, a header and an electronic distributer for my 73 240 L24 - so now it's gonna go on the a L28 (which will go in the 240). My question surrounds what can and cannot be done - I have the L28 in the machine shop now and based on information from good sources the P90 will work good with flat top pistons if the head is shaved .080" and the cam towers are jacked the same amount - should give me 10:1 compression. Only thing worrying me at all is that I just recieved an email from the machinist asking if the valves will clear the pistons when they are changed from dished to flat tops? Any advise or info? Thanks Rick