I'm looking to rebuild my 94 EFI 300 and I've talked to Comp, Crane, and Lunati. They've suggested cams but have been reluctant to put together an invoice for the internals because they don't know "how much room you have on the head" Anyone know what the stock clearance is and could explain what it means/why its relevant. I'd rather understand everything then just have an answer, thanks guys!

 

I believe the room they are talking about is your clearance for your compression area. Not entirely sure, but that's what is sounds like.

 

If that's true, do you know what it is?

 

It's the distance from the top of your piston at TDC to the bottom of your head.