The single center mounted two barrel progressive carb is the least expensive and also the least desirable setup. The long unheated intake runners allow the fuel mixture to drop out of suspension on the way to the head, causing a lean condition at low rpm. While the power valve is meant for an inline four with greater vacuum, causing a rich condition at higher rpm.
My car, unfortunately as many do, came with the single setup, seems to be fairly common in states with lesser degrees of smog control (Nevada has tail pipe test only '68- ). After a couple of years I found a used set of Weber IDF 40's. It was a completely different car, not to mention the looks of the carbs alone on the engine made the change worth it.
Now to keep the FI people happy, FI is by far superior to carbs. Anyone who doesn't think so can count the amount of car manufacuted today that come with carburation.
The hard part is the diffculty of completely replacing a nonexcistent stock setup or the cost of aftermarket units. In addition, stock FI units limit the amount of modification to an engine. Both systems, in my view, have a place on the 914, just avoid the single carb setup.
I finally went with an aftermarket kit from CB performance. Can't wait to see how it works, car should be back together this summer. Just sucks that the kit cost more than the car did
Chris