Hi,

My first thought was or if are you using the same cam over to either head?
I’m a 240 overhead cam guy myself so you see why my first thought could be valid especially if you get the shimming wrong way way off.

I have to say this is a very unique test result and want to say the common thread might be a possible “operator error.” At my age I have found that door left unlocked more than once.

Aren’t those engines a push rod engine?
I have no idea when fuel injection started either so the head swaps is exactly that way over my head! 🙄

1965 is pretty far back there. I think the Bendix Co. during the 50’s did experimental for aircraft and “hot rods” were abound.
In the sixties that work was sold off to the Bosch family. It was probably a collaboration to begin with.
Back then, if any devices running it would have actually fill up the back seat.
Like alternators were the newest thing in production.

Maybe you have a very flat cam lobe or or it’s way out of time.
Surely you would have seen wear it unless you left the engine in the car? On V-8’s the cams and hydraulic lifters is another ball of wax.

The latter about timing wouldn’t necessarily work with the other cylinders coming up in compression.
Even if a compression ring went in upside down it would still have some pressure as compression rings use pressure to expand themselves. The little bevel is important.

I don’t have any other ideas unless the engine was rebuilt before you by someone in the East Tennessee Area.
I from that state originally and was asked, while I was in the Navy, if I was a ridge runner?
I didn’t know what that person was asking.
He explained, that if so I would have one leg shorter than another.
I said no, I was from the west side of Central Tennessee. But I never forgot that one.
I never moved back to Tennessee either. Thanks partly to its stigma and the south in general.

So with that, did you compare the rods for length?
A 1/4 inch or less would make a big difference. 👀🙃
A Piston heads top or crown to the wrist pin height is another one. You gotta appreciate the hot rod people of that era. They became the muscle car engineers for the big three.

If I went way back to the days of “top hats” I bet there’s a joke in there somewhere too. 🤪

Lets us know what you find as I’m interested.

Phil