I just noticed today that McJacks is once again actually taking orders for their headers:
https://www.mcjackscorvettes.com/product/65-69-corvette-big-block-2-primaries-factory-cast-iron-replacements/
For a long time, they had a message on their page saying they had suspended taking orders. I'm not sure why. Now, it looks like they're taking orders again.
Anybody know the story? Anybody ordered since they started taking orders again?

My understanding is that their headers work with the factory exhaust pipes. So, you can "just" remove your factory cast iron exhaust manifolds and install the McJacks headers and use your existing factory exhaust pipes.

I guess I'm a little skeptical about how much power you gain if they are truly the same dimensions" as the factory manifolds. I understand that they are headers and have smoother insides, etc. But, they are by no stretch full length headers or the concept of headers that are used in racing to make much more power. So, I'm imagining putting them on and realizing they really don't make much more power than factory - so why bother?

Any of you running them and want to offer a testimonial about how much power they actually gained you?

 

I guess you checked McJacks site? They offer both the shorty and long tube version.
I bought mine before the interruption. I have been very pleased with McJack headers.
Good luck

 

I also bought and installed my McJacks BB headers back in 2019 before Covid and before McJack's self-imposed shutdown. I never measured the before and after horsepower gain or loss levels so I really have no idea if they for sure make more power. They feel like they make a bit more power, but that could just be my imagination. Much like buying a really expensive set of golf clubs and you feel like you hit better.

I bought them more for the look and partially for the weight savings. Much like a mono-leaf fiberglass spring or a mini high torque starter, the BB headers are much lighter than the OE cast iron exhaust manifolds that they replaced. They don't rust or discolor and look as good now as the day I installed them. And yes, they bolt up to OE factory exhaust perfectly whether it be side exhaust or through-the-body exhaust. No cutting, no welding and no adapting anything. I had my original exhaust manifolds "re-skinned" by Jerry McNeish up in Eldersburg MD. and they are down in my basement perfectly preserved and will go along with my car when and if I ever sell it.

McJack's was great to work with and their customer service was excellent. All of my interaction with them was by telephone; mostly with the owner himself. Yes, a set of headers from McJacks is a totally unnecessary (and likely unneeded) expense, but so were the red lines and bolt ons I just bought and installed.

The heart wants what the heart wants. Good Luck with whatever you decide to do. C.J.