Horsepower limit for out of the box Edelbrock RPM heads

turbodart68 said

That’s weird because I had me Eddy’s flowed and they flowed 215 out of the box. My X heads flowed 208 on the same bench. And 450hp from a 10 to 1 410 is low. My 360 with stock X heads and 11 to 1 made 397 hp at the wheels and ran 91 in the 1/8th at 3450 pounds.

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That's my thinking.
They don't barely do the numbers they say, maybe the best ootb set does ... but 3 out of 4 don't. Sub/par 500hp is what you can expect from a 408 with ootb eddy heads and sub .600 lift.
I'm sure you could hold the valve open longer, but it would be a pos on the street.

Fwiw I agree on the x head flow as well, best I ever saw was 218cfm. J head factory 2.02 228cfm best.