[SS Engine Guy]

First, it isn't unusual to spend upwards of 5k on a set of chev. stocker heads. At $100.00 per hour thats 50 man hours. Flow 5 to 20 pairs of castings. Then flow the best 3 or 4 with different valve configurations/seats/seat cuts and seat finishes. Then flow the best 2 or 3 with several different lift characteristics with velocity probes and sometimes wet flow the best 2 with 3 to 5 manifolds comparing the exhaust with a couple different exhaust tube sizes and length of bends just out of the exhaust ports. You will find heads that have flow figures where you need them that will somtimes be 30 to 40% different (better) from the best set to the worst. Being able to do this isn't something that can be learned in a week and there are only a very few left that can or will actually do this type of work on stock (legal and never touch a port or chamber) cylinder heads.
With that said, porting (illegal) a stock cylinder head is easy. And covering it up is easy. And no, it can not be detected by dyes, sprays, chem tests or otherwise when the person doing the welding/grinding/spraying/blasting knows a little about what he is trying to accomplish.What you need to know is that port shape is way more important than port size. Here is where the really big cost comes in. And atomization in the port is what makes the most hp. Velocity is more important than total flow in most cases and this has to start as soon as the valve starts to open and continue as completely as possible till when the valve closes. Some of the work in shaping a port is not as drastic as some might think and the changes can be hard to detect if time is spent trying to keep the port (looking) stock. This is an exact science that is still evolving as newer and newer technologys are available. With port shape analysis you are very likely going to spend way more than 5k on a set of stocker heads.
Here comes the bad part (if running illegal isn't bad enough). The rulebook in the santioning bodies used to say in SS that zero modifications were allowed in the combustion chamber. I was told that I could not even glassbead a combustion chamber to clean it as doing so could "smooth" the combustion chamber in a way that would be considered illegal. Also I was told that agressive use of a wire wheel to clean could get me tossed. Yet at the same time, I am taking apart pieces from the biggest names in SS builders that had the intake valves unshrouded as much as .200 thou., edges rounded off, obvious grinding and reshaping in the chambers, plug locations moved with absolutely little or no regard to attempt to cover any of this up. Some of these freshen-ups were record holders that I had personally watched go thru tech. Winners in class. Div. and Nat. winners, etc. I turned down countless jobs after taking this stuff apart because I didn't want my name attached to it. Then one fine day, about 3 years later, the combustion chamber rule gets changed. Making very few of these heads legal, by the way. And I still see obvious welding in the chambers even though the new chamber rule says thats not allowed. Still plug locations moved.
Wade, I have no idea how you are supposed to find out what is actually "legal" at the time as all I have ever been told was NO. Only to see what I wasn't allowed to do go thru tech with flying colors and if a techman ever questioned it he was over ruled.
Sorry for the long post but this is a really sore spot for me. My customers can and do run with the best in their classes-----legally. Fortunately, doing stuff illegal also means that you will screw your customer base also in most cases. You can't imagine the 28-40k junk that I have had in my shop. On a positive note, there are still some really fine engine builders out there that are fast and take pride in their legal work.