SBM Edelbrock/Speedmaster Head Data

Sorry for the confusion, but the two tests shown this time are both 50 deg. They are the same port, just showing the progress over 1 week. 1/8 identifies that it's cylinder 1 or 8, then the date is shown.

So, the bigger dip is a result of lots of work on the short side and some in the chamber.

And it is definitely an area thing. Once the short side is lost, a majority of the air is going over the valve and toward bore center. Finding area in the 0.550"-0.650" lift range is the key. It's hard to do. Laying back the short side helps some, but eventually the mid lift flow will suffer. I'm going very slowly at this point because I have a pretty good port going. Don't want to mess it up.

Haven't flowed with the valve upside down lately, nor have I tried the different test pressures. Maybe I'll try that in the morning.


Ok, I got it now. I’d test with different pressures and then flow the port with the valve upside down.

I think that might give some direction.

But your flow curves definitely have a strange dip.

I’ll be glad to learn what it is when you figure it out.