Speedmaster Small block porting tips and results Part 1
That's the balancing act that you do over and over again. air speed over cfm! If you can gain cfm without to much air speed you win. if you gain air speed but is turbulence. you ground in the wrong place. and you won't know until you try it!
And around and a round you go!
PBR knows were those "Do Not Grind" spots are and where the cfm flow spots are. So he can grind in several spot that he knows it needs. The fps probes just tell you if your thinking is in the ballpark.
Thanks for doing all of this pittsburghracer:thankyou::thumbsup::thumbsup:
I made This statement early on in this thread.
and now i feel i need to clarify it just a little
Grinding in the wrong spot just a little can turn the flow upside down. But thats when you trying to get 300 cfm out of a stock 340/360 head and you just got 285(just throwing numbers in the air)
A single seat cut to a 3+ angle cut is alway a cfm jump! bowl blending is a + in flow and so is cleaning up all the imperfections in the port.+++
If your trying to get more area around the SSR to slow the air speed down and you lay into the short wall all The way into the bowl. Look GReat!!!! BUT IT START TO SCREAM ON THE FLOW BENCH AND WHEN YOU PUT YOUR FPS PROBE IN........YOU HAVE NEGATIVE NUMBER..........yes the air has turn around and is coming back up the port. couldn't believe my eyes. Why? Because air goes where it want to, NOT where you think it should.
What i did was create a low pressure spot and now some of the air had a easier path back up the port instead of out.
This wasn't simple cleaning of the port or slight reshaping of the port. this was a big big chunk of iron i ground out.
What's being taught here i don't think you can go wrong, some may get more out of there head then other, but i don't think any of this will make the head worse. Only Better:steering: