Vacuum Question????

[chevy_guy]

I am running a 79 Chevy deluxe with a rebuilt 350 and 700R tranny. I have replace the intake and carb with an edelbrock 1405 carb and performer intake with an MSD street Fire distributor. On the 700R there is no vacuum modulator line so no worries there and I know I should hook up the power brakes to the back of the carb, and I know I should hook up the timed port on the carb to the distributor, but there is a vacuum port on the intake. Should I run a T in it and run one end to the timed vacuum on the carb and other end to the distributor or should I plug it.

[Fairlane514]

I would run your brakes off the intake port not carburetor.

Not sure why you would run the port from the intake to the carburetor. 

I would also run full manifold vacuum to your distributor, the motor will run cooler and have more total initial timing at idle. Such as 12 degrees mechanical and then 10-13 vacuum for a total of 22-25 initial.

[Irish_Alley]

what about the pcv?

[Fairlane514]

PCV....run it into the port on the base plate of the carburetor

[Irish_Alley]

lol i was asking him cause he didnt mention it

[chevy_guy]

Yeah I know the PVC goes to the big plug in the front of the Carb. SO you guys are saying that I should plug the power brake hole in the back of the carb and run  power brakes only to the vacuum port in the intake.

And for the distributor, I should run the vacuum hose from the manifold vacuum source (right side of the carb) to the distributor. Could you tell me why not to run it to the left side of the carb instead?

I am a beginner so dont take my asking questions personal, I just want to know to increase my own knowledge.

[Fairlane514]

There are arguments for both sides, (no pun intended)  as far as ported or full manifold vacuum for the distributor.  Running full manifold will let the engine run with more total advance (mechanical and vacuum combined) at idle and at cruise. This will help with mpg and temperature.
I run my 84 C10 with a Goodwrench 350 and HEI distributor (adjustable vacuum advance) at 22-23 total timing at idle. It loves that comb inaction and fires right up every time.

You can try both sources of vacuum on the distributor after you set the timing (with the vacuum unplugged), and see what you like.

As far as the brakes, it doesn't really matter if you go off the carb or manifold.   I'm not real familiar with the Edlebrock carburetor, but obviously the brakes need full manifold vacuum.