Looking to add extra fasteners to the middle flanges 440/906 heads. Who's done it, any tips?

You mean a second one as a lock nut?

Dang, I posted a pic but it didn't take.

Its a pic of the centre flange for 3 & 5 tubes, where an extra stud has been added on top and bottom to snug up the centre part of the flange. It was a from another thread here on Moparts. I can't access the pic form work, I'll try to post again in the AM.

Edit: The pic did upload - I just can't see it from work.

Nobody's done this ?

Thats a beefy flange, doubt you needed it. Interesting idea, I would be afraid of cracks off the exhaust ports.

I think it's a great idea. Not only for the pressure it places in the middle of 2 ports that only have 2 bolts now but for stability too.

I admire the small block for it's 2 higher studs on the end and small Fords for their staggered bolt pattern. One up, one down etc. BB are all inline.

Where I see that as a minor potential problem is when the engine moves around on it's rubber mounts. The exhaust system is constantly yanking on the header assembly. This may eventually crush the top and bottom of the gasket, leading to a leak.