I've been packratting parts, as these motors were not popular and they're all ancient. Cylinder heads especially since they often crack. There seems to be a lot of tiny variations to the same casting for inexplicable reasons, luckily all are interchangable.

This is a "trough" type intake, cast-in-head like many early sixes (Chevy, Willys). Cheap to make, performance poor, and it makes the engine ver narrow (good, here). A cast flat aluminum plate over the trough means making turbo and EFI adapters easy.

Just got two cores back from the local machine shop for cleaning and inspection. One came from U-Pull-It, off a 63 Classic that had a ventilated block, and a clearly, recently rebuild head. Nice find! The other was a junk motor pulled from who-knows-what and picked up for free by me out of someones storage unit cleanup. This one had water in the oil.

The Classic head that looked so perfect turned out to have a very well done repair to a crack in #6 cylinder exhaust valve seat. Burned #6 sounds to me like a plugged up water jacket with no coolant flow in the back of the motor (slight tilt rearward). When I got it the head was nicely painted, different from the motor, so I assume it came from commercial engine rebuilder. See photos.

Here's an unrepaired #6 for comparison.

(The red paint marker is approximately where the water jacket falls, determined by poking wire in there.)

The other head cleaned up nicely, with not much wear, and no crack damage. This will become my turbo head. The only substantial difference with this block the lack of tapped plugs into the water jacket between the exhaust ports.

The only head work I plan on doing is to polish the exhaust ports and valve bowls as much as I can to minimize heat pickup, as it seems to me to be a major design limitation: exhaust passages are long with two 90's, and anecdotally, this motor warms up -- produces usable cabin heat -- within 2 - 3 minutes of driving. That is is coming off the head!