[Carnut427]

The low riser intake is a match for 428 Cobra Jet heads, but we don't know what size ports your Edelbrock heads have. Your best bet is to call, email or fly to Edelbrock, tell them the part or casting number of your heads, and ask them what size the intake ports are. Either that or pull your intake and measure. I did some research (yes, lazy me!) and here are the port sizes listed by gasket manufacturers; the first three are Felpro's sizes, and the High Riser is from Mr. Gasket. Note that actual port sizes will probably be just a bit smaller. You can put a Medium Riser intake on any head with the possible exception of the High Riser. It's better to have a smaller intake port going into a larger head than the other way around. As a matter of fact, a lot of engines come from the factory this way. If you have enough metal, you can port match them for a better fit if you wish. The carbs are mounted higher on the Medium Riser intake, giving a better shot to the valve, increasing horsepower. Yes, the BJ/BK carbs are progressive.

"Short" Low Riser port 2.10 in. x 1.40 in.

"Tall" Low Riser port 2.34 in. x 1.40 in.

Medium Riser, 2.22 in. x 1.40 in.

Ernie's "Tall and Terrible" High Riser, 2.90 in. x 1.50 in.