I did a review of the Hedman shorties and my X-pipe exh on the Drydock some years ago, don't know if it's verboten to link to other sites, but that's where the info is. Gosh that's been 10 years already! Is installed on my white Fury in my sigpic.
I had some difficulties in tuning the car afterward, I later learned that the issue was the POS Eddy 750 carb, which the headers perhaps aggravated. I installed an 800EPS maybe 4 years ago and things got a lot better. I am running a 69 T-code 440 and its original tiny 256° cam, Eddy Performer intake, and the carb mentioned (all else stock).
I don't know if these are superior in performance to HP manifolds, but considering they are cheaper and faster/easier to find I don't think you can go wrong with them. If you have standard log manifolds you'll need to modify your headpipes for either HP manifolds or the shorties.
My headers are still in decent shape, they have some flashrust on them as I don't drive the car as regularly as I used to, but still no leaks or anything. I've had none of the header issues that give headers a bad name. I used a particular brand of copper gasket (one that has a small SAP opening, and not the bigger squarish max-wedge port size like most copper gaskets). I initially tried a set that had that larger size and one header/gasket leaked at a corner of one tube (but they would've been fine for sealing a manifold).
I'm frugal with my money, so I won't buy an $800 set of headers, or a $550 set of headers, when a $200 set will work probably nearly as well. And I liked them so much I bought a 2nd set to install on something else, just in case!
Forums / Performance Tech / Hedman shorty header review - C-Body DryDock
Forums / Performance Tech / Hedman shorties, X-pipe kit, TTI tailpipes - C-Body DryDock
Fotki became a pay-site, so the links in these threads go to a suspended page...