Currently have 44's that were just rebuilt, my experience is that 44's are a little big, and you need at least 2200 cc's of displacement to fully utilize the throatsize.

What's your experience/advice/opinion?

You can use smaller venturis on the 44s, i ran 44s on my 2056 with 32 venturis and they worked well.

I started with bigger venturis but could never get it to run quite right until i downsized them.

You need the velocity and vacuum for Weber’s to work correctly. If you think of it, a 2.0 liter 914 has the same displacement per cylinder as a 911SC, so most of the tuning should be similar. Red Paul Abbot’s excellent explanation on weber carbs at his Performance Oriented site. It should be required reading before anyone takes on playing with carbs.

BTW, if you’re using a stock cam, the original fuel injection system will probably run better than the carbs (though it doesn’t sound as nice).

I'd go with 40's

Common sense.

the correct answers are in the Weber Tech manual by Bob Tomlinson

look it up on google & BUY IT

.

GR -

Rebuilding my 44's now, the venturi's are 45's......have yet to start the engine but it was running perfectly when parked in my friend's barn 10 years ago. Local Porsche dealer here put the 44's on.

The PO, who used to race 911's, said the 44's didn't produce any more power than the FI BUT made the engine far more responsive......change was made because dealer could not find ECU for the '76 - or so dealer said - dealer here does NOT have a good reputation.

SO, I guess I need to get the smaller venturi's ASAP.....I ordered the Weber Tech Manual last week and should get it this week.......

Thanks!

GN

You won't have 45mm venturies trust me on that ...

You will see lots of opinions on this. I went with 44s and they were too big until as it has been pointed out, I downsized the venturi's.

Many have more experience and likely have better advice but I would go with the 40s. They are a closer match to what your engine will need and going through the process of buying different venturi's, jets, mains, Emulsion Tubes...... and on can become expensive and a real headache.

The 40s comes stock with 28 Venturis and they were capable of giving my 2056 all it needed. You can go up to a 36 Venturi on the 40s but you will be hard pressed to ever need that. Note the 44s come with 36 Venturis so unless you plan on making it a "TOP END" performing motor you can get all you need from the 40s.

Click to view attachment

Good info,running dcnv Webers on one of my 1.8 T4's ,the throttle response is excellent with 27mm venturies,I have another motor slowly going together and that will have 36mm Dellorto's with stock (from factory) 28mm vents.
When I did my Zeniths up I first tried 32mm from factory 27mm size ,it had a noticeable "hole" down low and not so smooth transition to mains,moved down to 30mm and hit the "sweet spot" ,was easier to tune also.