Can any one out there comment on the idea of cutting off the 6 inches or so of the heat exchanger where it meets the heads and adding flanges there so that the exhaust can be dropped without disturbing the head joint?

I have a spare set of heads so I ws thinking of mounting the heat exchangers, slicing and then tack welding the flanges while still in place. I was thinking of using V flanges with rings as well so you could still get to the head studs with a socket.

Ideas?

It'll work as well as you can weld and fabricate.

With the massive PITA of removing these exhausts and the risk associated with messing up the studs, I have thought about this myself.
I am even keeping a nasty old set of HEs just for this purpose

Yeah. Well I tend to agree with that one.
Given that I pull it off - is it a reasonable idea? I find that I want to pull the exhausts to do things like check the valves, replace an alternator and track down pesky oil leaks. Now that I am backdating to 1974, I am not gonna have the two into one sink p trap to disconnect anymore. Thank goodness!

The port end of SSIs is rather flimsy.

Meaning they wouldn't make strong stubs? What if I used the port ends of stock 1976? I appreciate that you are following this Chris. Trying to put together a six and keep the 4 running at the same time has required bargain hunting. And of course I like experimenting too. Haven't the er thingies to drive as fast as you do though.

Exactly.

I guess, if you can make them fit up to the HE pipes.

Would it help to tie the two stups together with a cross brace? Assuming room which I am not so sure of.

Expansion and contraction may be dissimilar from the heads. By locking the two together it may cause a leak. It's a puzzle with lots of trial and error to get it right.

i think if you take 6" off of the head ends of the heat exchangers you'll be into the bottom curve of the pipes. you're going with stainless?

Yeah, I would say that is correct. I have experience welding stainless, and thought it worked well. I might fill the tubes with argon. The welds will be to flanges, not directly joining tubes.

The curve is a problem. One solution would be to cut the stock stubs off at the point they start to curve and join to a straight point on the new stainless. That way, the HEs would drop down and that might magnify the problem.

I ordered the flanges, but I have a lot of things I never used...

I've thought about doing this to my car as well. It would be cool to be able to run heat exchangers in the winter and then headers during the warmer months. I was thinking of using stubs from a European Racing header. Those damn studs break too easily when removing the exhaust. Is there a type of exhaust stud that is not so fragile that could be put into the heads?

Remember that the j- tubes, branch ducting, warm air elbows will all be dropping too. You'll have make it all work and connect to the fan shroud. Heat control wire too.

Yeah, we kinda ruled that out last night drawing on a paper bag. My son asked: is this common? It seems convenient. My comment was I had seen it in some of the higher quality headers. Never seen an add on to HEs though. Odd. I am always the last one to know etc....

I measured a set of ss heat exchangers, vendor fuzzy. I got a wall thickness of 0.080 The stock came out as 0.125 That would very strongly substantiate what Chris said.

The whole point is to leave the joint at the head unmolested while pulling the exhaust.
Query: is this really worth a stub joint and flange effort?
Query 2: Why do we see stubs on the better headers if not for this reason?

I have discovered I can make it work with ss HEs. Do I want to?

Don't the later models already have a two into one setup like this?

Didn't someone make aftermarket headers and exhaust sytem that did just that? I remember looking into that system a couple years ago, but apparently the guy who made the system died and the idea must have died with him...

This would be a one into one setup to get rid of that. I am backdating a '76. But yes, I would like to retain that stub aspect.