91fireturd305

Allright my question is about the short side radius. When porting the heads should i just smooth the radius so that it has no ruff edges or should i actually try grind it down a bit to let the air have a shorter drop off in to the seat. This is my first time and i have bought some books but no real good closeup pics or explanations of the short side radius. thanxs for your help.

RB83L69

DO NOT shorten the short side radius!!!!! You want to keep the air flowing at the roof of the port, such that it hits the back of the valve as parallel to the valve stem as possible (staright towards the back of the valve, not at an angle). All you should do to the short side, is smooth and streamline it. DO NOT lower the floor, or cut the short side back, or any of that; basically, that destroys a head that otherwise might have potential, if it's a decent casting in the first place. Turns it to scrap.

Streetiron85

It probably depends upon the type of heads you have.
But I have always made the short side radius into just that. A radius, that includes or blends in well with the bowl cut.
Anything is an improvement over the "corner" that the factory puts into their iron heads, where the short side radius should be. As long as you don't overdo it and make it so the moving gasses have to make sudden wierd changes in direction once they reach the bowl.
It's bad enough that the intake charge has to be forced around those curves to begin with. And anything that you do to make the curves sharper, harder, more irregular tends to cause the gasses to want to break away from the curve of the port at high speed, and go in their own direction. Sort of similar to a car on a track at high speed.