'73 914 2.0 air/fuel issues

[gredbeard]

I have a '73 914 with the 2.0-4 engine. I bought the car several years ago, and at the time, it was advertised as having a "rebuilt engine". The car was very clean and ran well, so i had no reason to question it at the time. It has dual EMPI carbs.

I've driven the car quite a lot (and enjoyed it), but over time, managing the air/fuel mixture has become increasingly challenging. I've experienced some combination of carb popping or backfiring from muffler, (or both) depending on carb balance, etc. I've spent countless hours learning and and adjusting timing, (replaced to electrontic ignition), balancing carbs, etc. Even pulled the carbs and intakes to clean and reinstall with new gaskets. I can even feel that when it's running worse (seems to be even dependent on the weather) that it's not pulling like it should... When it's running well pulls great. Also seems to run better when the engine is cold than once it warms up.

I've gotten to the point that I've even wondered if, during the "rebuild", perhaps the cam was not matched to the carburator setup? And also wondering if the EMPI carbs (and/or intakes) are simply inferior to other options. often seems like there's an intake air leak causing inconsistencies. At this point, I don't really want to pull the engine for a rebuild but would be open to:

1. replacing carbs/intake with something higher quality (weber?);
2. replacing carbs/intake with stock intake and FI (if that's even purchase-able;
3. replacing with a more modern and controllable FI like Megasquirt.

I would love to hear feedback from the group? and also curious to know if it's possible (without a build sheet or opening the engine) to figure out what cam it has? I suspect during the rebuild, they kept the stock cam but added the carbs, but I don't know how to tell?

Thanks!

[dr914]

have you adjusted the valves recently?