The NHRA tech inspectors have seen every trick in the book when it comes to cylinder heads. They also have an engine blueprint sheet telling you what part # pistons you have to use, what deck hgt. you have to have and combustion chamber size for the head. The cylinder heads cannot have a die grinder, file, sand paper or any other device touch any part of the ports, chamber or bowl area that can remove or modify those areas in any way other than the valve seats. Same goes for the intake manifold. An NHRA tech inspection can be more brutal than an IRS audit....
