I hope someone has some experience with this!
I ordered and received some Hedman Elite headers for my ZZ-4 crate (with D-port heads). I was lead to believe that I did not need D-port headers and that it was a matter of preference only! The reason I didn't like Hedmans D-port version is that they were only 1/4" flange and I feel better about 3/8" flange on the Elite product line.
Looking at the headers I received I was surprised to see that the mounting flange was not flush but a small protrusion of tube with some weld around it was sticking out of each port.
Is this protrusion intended to flushly mount against the head or fit inside the port?
From a strength point of view it would make more sense if the entire flange was the intended flush mounting surface but that's not what I am hearing from Summit. That means that if I torque the bolt too tight I will distort the flange.
Does this make sense?

 

Don't worry about it. Put a quality header gasket on there and you'll be fine. I have Hedmans also and have had zero sealing problems.

 

I have hedmans on my zz4 and am not happy with them. After breaking the engine in, they warped badly enough that it's now nearly impossible to get them to seal. Maybe I jus got unlucky.

 

Rule #1: Headers are a PITA. I have a set of the Hedmen Elite Super Comp coated headers on my '70, 350CI Corvette. I have the stock #186 heads with the small valves and I'm not impressed with these headers. They don't seal that well even using FEL PRO Ultra Seal gaskets. I also had the exhaust ports matched to the gaskets. My headers are warpped, so I use GM metal clad individual gaskets on top of the FEL PRO's to assist in evening it out for a better seal. At least I can't hear the leaks.

I'm also not impressed with them passing so close to the oil filter, but that is another story.

Good Luck!!!!