I figured there would be someone here who would be more knowledgeable about engine combinations than myself, so here's the info:

'68 2.0L 'L' motor.
'69 'S' pistons
Standard 66mm counterweighted crankshaft
center-lube Solex cams
stock air injection, small (tiny) valve heads.

I originally purchased the motor as a fuel economy option for my 914 as my RS 2.7 sucks down gas like crazy, and I daily drive my 914. It spun freely, and it appears to be pretty clean on the inside, despite the grime buildup all over the outside of the engine. The 69S pistons were a nice surprise, as we're the solex cams, as I assumed it was just a stock 2.0 'L' motor.

So far ever internal component has checked out to being well within spec, with the exception of severely worn valve guides.

From a combination standpoint, what should I expect out of this engine? I know the valves in the heads are restrictive for the solex cams, but the valve size should keep port velocities up at least..

The main goal is to not spend money on big components. Rings, bearings, valve job, all will be done. It would be really nice not to dump money into cylinder heads though.

So, what say the experts that know way more than myself?

Interesting that you mention the "S" pistons and small valves. "S" pistons have large reliefs cut in them for the larger valves need to make the higher horsepower. Not sure why a combo like that would be done.

Only thing I could think of is that 69S pistons have a static CR of 9.9:1, which is significantly higher than a stock 911L.

My main fear with this engine is the risk of detonation with the small valve L cylinder heads which have a smaller combustion chamber, combined with the already high compression pistons. Obviously this motor ran this combination for a long period of time, but that certainly doesn't mean that it's correct.

Here's some pictures for proof.. yes, the intake valve is about the size of the cutout in the pistons for the exhaust valve.. HUGE valve pockets in comparison to the valve sizes.