SBM Edelbrock/Speedmaster Head Data

Newbomb Turk said

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.

Click to expand...

I think it could be chamber shrouding on the long side. The valves are sunk 0.080 to 0.090. This means there would be that much additional shrouding on the plug side. Look how quickly the flow rises at 0.700-0.950 lift. The valve is getting clear of the chamber. I bet a surface cut on the deck face would clear it right up.