Hi,
I'm giving serious consideration of changing direction on headers. I have a 69 car that is for the most part stock (350/300 auto), and I've got Hedman (longs) headers and 2.5" N11 exhaust. Outside of the headers and no smog, it's all stock and I want to maintain that look (wires and most of the shielding). I have a few concerns with the headers when I got them mocked up and it's caused me to perhaps go with the McJacks instead. The Hedmans are very close to the idler arm, like 1/8" and about 1/4" from the steering cylinder. The wires are also extremely close and if routed properly, will touch. So I've got to re-route those the best I can and likely get boots etc. so that I don't burn wires etc.

The McJacks seem to fit like the cast ram horns but have a shorty header performance and sound. Plus, they will mount to the new exhaust with no mods where the Headmans need cut and fitted etc. I don't see a bunch on the net about them (or at least recently) and wondered if anyone is running them - how do they fit/install (any problems with gaps or leaking), perform and has the coating held up etc. I've attached a pic to give you an idea of what my setup is. If you have any pics I'd like to see them. I've got what i thought was a decent amount for the Hedmans and the McJacks are even more, so I'm trying to be impulsive.

Would love to know what you guys think?

 

I switched to a set of McJack headers on my BB several years ago. As far as construction goes I feel they are very well made with nice thick flanges etc.Welding is tidy, maybe not aircraft quality TIG or anything but whoever welded mine knew what they were doing on that day.
The copper (inside) has some black but hasn't clipped or anything and ceramic coating on the outside looks pretty much exactly as it did new with little if any discoloration from heat or anything, maybe not quite as "bright" and does need a cleaning once in a while, I've done it twice in 4 years otherwise it goes dull, more of a layer of film on it than a discolorization of the coating. cleans easy
Fit was perfect, bolted right up to a set of "stock" 2-1/2 aluminized pipe from corvette central using the standard donut. Clears the steering box and everything else nicely without issues. Spark plugs are tight as the bend is close on the #1 (BB but I imagine the SM would be similar) I installed a set of the woven boot covers this year mainly dur to the #1 135 boot being so close it was starting to melt some)
No leaks at the block or flange connection and it's been apart and back together numerous times.






Expensive and still a shorty header/manifold rather than a long-tube but I don't regret the purchase
M