[DPWU]

Alright, so I've got my unit 500 engine almost entirely disassembled, and I'm getting ready to order bearings/gaskets/etc to start the rebuild.

My issue is that I'm not 100% sure what I've got. My engine was part of a basket case project I bought, and my cases have no VIN stamped. Yes, I know where the stamp would be, no there is no stamp, no marks, no anything.

So what I've got to go from are parts numbers of the cases, crankshaft, etc.

Here's what I've got, anyone able to tell me what I've got? I know the engine has been apart at least once or twice before, most recently was pre-1985.

Crank/Flywheel - E3712
Timing-side case half - Casting #70-9035
Primary side main bearing race - 90125A
Final/4th gear - 57-3991/2

Those are just the numbers I've got with me at the moment, but I've got a bunch more taken from various other bits.

 

[DPWU]

No distributor, definitely points. Timing side case has a ball bearing.

The top-end was off of the engine when I acquired it, so I'm not 100% sure if I've got the original head. What should I look for on it specifically? I got two Amal 626's, but in my basket, got two carb spigots (to run duals), as well as the 1-2 manifold (for running a single).

 

[DPWU]

Pretty sure that the numbers may have been ground off of the case many moons ago. The engine has been in pieces since at least 1985 (based on newspapers some parts were wrapped in), possibly earlier. Bought the basket from the estate of a brother of a friend, and he may have had some seedy friends back in the day... Have a legit frame to drop the lump into once it's rebuilt, just trying to figure out exactly what I've got, so I order the right parts for the rebuild.

Were the heads different between the single and dual carb set-ups, or was it just the spigots/intake manifolds that were different? Obvious differences to look for?