Weber Vacuum vs. Pertronix 1 SVDA" Distributor, 12 VOLT, Need to know if I can just tap the intake manifold? Options

[mturner7]

Hi Everyone, This vacuum connection to the weber carburetors has been talked about 100 times, but I need to address it again.

CAR/Engine:
1) Porsche 914-4: 1975 1.8L big bore build, dual IDF 40 Carbs

2) I have Weber 40 IDF 19 's with no vacuum port

3) I have a Pertronix 1 SVDA Distributor, 12 VOLT with electronic points

4) I have two sets of intake manifolds
- One set has a port already drilled and plugged see photo
- The other set does not have a hole/port

5) Since my new Pertronix 1 SVDA Distributor, 12 VOLT has the combination of centrifugal and vacuum advance installed.

6) Can I just remove the plugs in the intake manifold and add the vacuum line with a "T" back to the distributor?

7) That's the way it is connected in my 1974 Porsche 914-4 2.0L car, except the car has dual weber 44 IDF's with a vacuum port on the bottom of the carb itself.

8) Please help, I'm in the middle of my build and coming close to installing the carbs, intake's, and distributor.

p.s.: I have two sets of intake manifolds, the holes that connect to the carbs are different on the two sets.

- 48mm for the short ones
- 40mm for the long ones

The 48mm ones were on the engine with the weber 40 IDF's
The 40mm ones were on a car with Weber 44 IDF's

The 48mm ones have the port driller and tapped.

Will it matter which one i use>? 40mm hole or 48mm hole?