Valve job on os valves
What people don't realize it that when machine shops talk about "three angle" valve jobs, they're not talking about anything special. Every single automotive and light truck engine from our era came with a three angle valve job. That's a stock factory valve job. Machine shops have cut that corner for DECADES acting like when they grind or cut a three angle valve job, you're gettin somethin special, when you're not. They grind or cut a simple single angle for the speed of gettin it done and out the door and lower total cost. You can verify this easily in most any factory service manual that details a factory valve job and gives an explanation of those angles. Most shops refer to it as a "competition" valve job, but there's nothing competition about it, although certainly it takes more labor to do.
I didn't think of that, either. All I remember from the FSM was that IF the 45* seat winds up being over "so" wide, to narrow it with another angle of cut. though it has been a while since I have had my head into that part of an FSM.
and back when I was 30-some years younger I remember from my Dad's old Chilton manuals in the back "unit repair" section I remember talk about a "competition" valve job. and alot of notes at the bottom of each step with a single star or a double star indicating "optional" extra steps, and I think the double star was " optional increased performance" things you could do but didn't have to. Among them, I remember a starred item along the way, was to "CC" the combustion chambers. which by, of, and for itself, does nothing for performance.
The OS valves can't hurt, especially with some porting.... something else I've had drilled into me, regarding the heads on the /6 was that they were originally specc'd out for the 170 CID version and unchanged and just "slapped onto" the 225s. Pretty much regardless of how the short block is built, or whether it's still as built by the factory/ or what you want to see different after, vs before. That, plus a compression boost/ which I can see that you are already talking about, can only help.
I dunno if he was being "funny"/ like people are when they claim a HP boost just by adding chrome, or serious/ but when the machine shop guy seen what I'd done to the head I'm running, he said that it was a "fantastic start" and that by itself, that my porting work "should add 20-30HP to my build by itself". He just "touched up" a few things, mainly finished the gasket match on the other end of the ports/ which I had barely touched. We shall see. Most of my performance measures will have to be limited to a before and after "butt dyno" comparison.
