Cylinder Heads 101

I agree with all of the theory BJR, but numbers need to be taken with a grain of salt. I would caution the use of exact figures in any dyno room, or flowbench. Thoose are simply tools. I can make almost any number I need appear on a flow bench, that doesnt make it accurate. This is not an attack on you, just an observation. Your results depend on your equipment, your location, and your methods. The only way to get accurate readings on more than one head, is to have the same guy, in the same place, on the same bench, do them back to back, recalibrating after every head. I dont take any numbers as exacts..You can only use them as an indicator orf a trend, nothing more. Dynos can be way off too, again depending on the situation. Also, using an alcohol engine as an example is at least in my opinion a little deceptive too..lol. Impressive, but deceptive to a new guy. Just some more random thoughts from me anyway....