My home inspection of Speedmaster heads

What's happening at .300-.400?

Click to expand...

What’s happening is....... for a ported head with a 2.02 valve at those lifts........ they kinda suck.

From a flow standpoint, the valve job sucks, and the throat is too big.
There is essentially no top or bottom angle....... so there isn’t a properly shaped transition from the bowl out around the valve and past the seat, so the port can’t move any air until you get the valve way off the seat and out of the way.

For the typical street/strip guy........ running these ootb isn’t going to be the magic you were hoping for.

They have potential...... as seen by the .600+ flow numbers.
But they’re not anything special ootb.