Speedmaster head hypothetical

Earlie A said

Single blade cutters. The throat is now epoxy which does not hold an edge as well as the steel would.

Just curious. Why do you pick out the 50 deg seats as being bad at low lift. The 45 deg seats should be better than the 50 at low lift.

And a smaller throat will help low lift flow on a 50 deg seat. A larger throat helps high lift flow.

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I know there’s epoxy in the bowls so you do have to deal with that.

You are making my point. The curtain area is smaller with a 50 degree seat. So you are shrinking the bowls (or a better way to say it is keeping the bowls smaller as a percentage of the valve size) so when I see gains in low and mid lifts I know someone is porting for flow numbers and not necessarily power.

On the exhaust side the port will keep flowing more the bigger you make it. That doesn’t mean it will make more power. In fact it probably won’t if the port is big and noisy.

I was lucky. The guy who told me about these steeper than 50 degree seats was pretty sharp.

Also in one of Dan Terrell’s books he covered steeper than 45 degree seats. There is some good stuff in that book but I can’t think of the name of it right now. Maybe it’s horse power secrets or something like that.

I guess I’d want to know what the sound differences are between the two valve jobs as well because that says a lot too.

Like I said, your ports from .350 on are not backing up. That’s critical. If they flatten out that’s ok, but when the curve breaks over and never comes back you know the power will be off.