Angela (and everyone else),
I called the man today and he told me that the engine is, indeed, a one-year-only production intended for the 1969 911E. He said he was sorry that it wasn't an "S," but that if it had been an S, I wouldn't have been nearly so lucky.
He said you might have found one of these in the odd 912E or in a shop missing key parts later on in the 70s, since they were only briefly issued and something of a "dog" (his word) compared to later models with increased displacements. He suggests that for a 1,500-lb. car like mine, this will be ideal in terms of both maintenance and reliability, but that I can abuse it from time to time without too much worry.
He talked for more than a few minutes about the organizational management in Germany, and how a parts bin for a 1970 car might contain parts from a 1956 run, if the parts were common, and that engines and transmissions were installed in whatever they were compatable with just to move them out as late as the end of the 60s. He stopped short of saying the alpha-numerics were created to describe what bunch of parts were put together when, but that was the gist of what I understood. He said you'd expect to find a fuel-injected 356 late in the run, with a four cylinder engine in it, and that you might find the same fuel-injected four in a 912E. If you wanted your 912E upgraded, this two-liter might be something you'd ask a Porsche mechanic about as a post-purchase upgrade option -- and the transmissions and so forth made it easily enough done.
I don't know one air-cooled six from another, but I'm going to start doing homework pretty quickly. If he's blowing smoke up my skirt, he's doing a pretty compelling job.
Sounds like he's picking up what you're putting down, though. I'm pretty sure he knows EXACTLY why I asked him for a number, but he trusts me not to do something shady when he's willing to part with that thing for some simple labor and a handshake that I won't sell it to someone for a quick buck.
I think he really wants to put this in my Hoopty. He did say that mid-mounting it was not what he had in mind, and that the extra fifty pounds or so of engine weight (between this thing and the Type IV I already have) was going to be trivial versus all the tubing and fuel weight in the front of the car.
I didn't ask for finite details, but I did ask him for that engine number. He's going to get it for me, and he's going to make sure I have an "adequate" supply of replacement parts. I asked him what that meant, and he said that when I hit about 100,000 miles, I might need a few things. He's going to make sure I have one of every moving part -- and six of several others -- as shop spares.
He estimates the engine to be good for more torque than the 2366, and says it has potential to dyno around 175 horses at 6,200 rpm.
He said he was aware of the rarity of the 911E, and of the mechanical fuel injection system, and that's part of why he's stockpiled the parts he's got. He was saving this for a rainy day project, and apparently the Hoopty is it.
The Type III in the first picture is his, too. The second photo is one I hadn't posted yet; since the car's sitting outside under a cover right now, that's here to keep me motivated. It's been raining like it was Seattle around here lately. Talk about timing for the poor little guy to be stuck outside, huh?