Blocking the heat crossover, IN the head.

Well, who do you believe.

I spoke with a very well known engine builder/head porter on the phone today and he said do it, it will help.

Sure is a controversial subject, lol. But, that's why I posted it.

Then go for it. I most certainly don't know much, but I know I have tested it more than once. There was ZERO power in it. Didn't find any driveability in it (which is quite subjective in itself) either.

Some guys do stuff because it makes them feel better. I got over that in the last decade of the last century.


FWIW if you tape off the exhaust hole in the head face and flow the port, you will find ZERO flow gain. Then you can block it off inside the port (with some screwing around) and you will get the same zero result.