I am curious and might want to try this.

Has anyone ever tried to install a late style muffler with the 2 trapezoid shaped 2 hole connectors to an early style triangle shaped 1 hole heat exchanger?

Do you follow? I'll hunt some photos up and edit later.

I know it might be easier to just get an early HE. But I am ready to try and re-invent the wheel.

LATE exhaust gasket:
Click to view attachment

EARLY exhaust gasket
Click to view attachment

No offense, but dumb idea. Do yourself a favor. Backdate the h.e's. Your engine will run cooler and have a few more ponies. Its the header design that 90s forward, then 180s to rear that lacks

Probably so.

Nobody has tried it because it's very difficult and gives you basically zero benefit.

If you want to cut and weld stuff, you could probably manage it. But there's no good reason to.

--DD

The wheel doesn't need inventing. Backdate the exhaust already and spend the time you would have wasted on that project working on another part of your car.