273/318 Heads
I have xheads, they are on my engine though. I just figured I would practice on something before diving right in... plus I'd be able to keep driving my car until confident in my "abilities." LOL
What is SSR?
If you are actually a dentist, you ought to be able to port very easily. Not much different than grinding out a filling, or shaping a tooth for a crown or whatever.
I can grind with electric, but I don’t like it. I prefer air. I have some some burrs that are 3 inch shanks, but most everything is 6 inches. Use whatever cutter it takes that makes your heads shape the port the way your eye sees it. There is not a wrong cutter to use (most of the time) if you get the shape you want.
SSR is Short Side Radius, and it’s also called the short turn. It’s the floor of the port where it turns into the bowl.
I don’t think those heads have any value, but I don’t think any of that style of head has any value. I may very well be wrong.
Whatever you get to grind on (it can be GM junk...it don’t matter what name was on the valve cover) you need to learn to make the shapes you want. Once you master that, you can port anything.
If you don’t have a sonic tester to see how thick some of the critical parts of the heads are, drill some small holes in the head where you want to see section thickness. That’s as important as anything else.
Once you start grinding, grind through a bunch of spots. Learning to see when the metal is getting thin can only be learned by doing it. Much better to learn on junk than a head you want to use. Cast iron isn’t nearly as easy to weld as aluminum.
Porting is about shape as much as it is about size. Almost every exhaust port is way too big already, so making it bigger is a power loss. Air like another fluid HATES to change direction AND it hates changes in cross section. If you are going to make air go around a corner, you better know why, and do everything you can to make it happy air as you force it to change directions.
Same with changes in cross section. Taper isn’t the same as cross section changes.
You can’t learn to port without doing it. Reading some good books helps, but you have to do it to learn it. Don’t be afraid to make mistakes and grind through places and get a look at it.
It’s a dirty, thankless job.
