I've flow tested a stock D3VE 460 head with stock valves and everything and they are terrible! The exhaust is as bad as it looks, I can fill the bottom half of the port with clay and it helps the flow about 15% with no other changes. I've also flow tested a ported iron CJ head and while the intake port would go over 400cfm the exhaust would only make 188 at 700 lift! Edelbrock says that their heads will flow over 200 on the exhaust with 600 lift at 28 inches of water, and acording to their numbers, there was no lift point that even the ported CJ was better until over 600 lift on the intake! It looks like Edelbrock put some thought into their heads and they are trying to make the best and most practical street combination possible. I've used the DOVE-C 429 heads on a flat top piston solid lifter 460 with great results, but these would sink that easily!

I'm thinking about building a 514 for my pickup truck to run on the street and the Edelbrock head is looking like it will be a pretty good choice. Sure they are not cheap, but I don't think I can live with the 128 cfm @ 28 inches that the D3 head exhaust offers either!