Edelbrock 2.055 (30 degree back-cut) testing

Rat Bastid said

I use 50 degree seats on all my street/strip builds. Been doing it for years.

The shape is better than a 45 and far better than a 30.

The 30 degree seat is an example of flow numbers on a flow bench sending you down a loser rabbit hole.

Guys get way too wound up with what is happening at .050, .100 or even .150.

If you know what your valve opening is at TDC you can see they ain’t open very much and the piston is right in the way.

Thats a reason why piston shape and valve notch depth is so important.

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DV in his BBC book goes into piston porting. This is relieving the valve pockets in the piston crown while the piston is close to TDC and the cam is on overlap. You are correct. A bit of relieving those valve cutouts goes a long way to keep especially the intake from getting balled up against a 90° wall and fairly sharp edge to the crown.
I wonder what would be the flow change if you had the crank, rod and piston in a cylinder, and just the intake valve in the head. Set the flow bench up to suck on the exhaust port with the crank at say 10° or 15° ATDC where the intake valve and piston come into closest proximity. Perform the test with and unported piston, then relieve the piston and test again. This overlap period in the engine is very important to power developed.