Holley 750 ??

Posted By: GoDartGo

Holley 750 ?? - 07/05/12 02:12 PM

I'm new to the 750 DP.

So, what is the vac port for, that is on the front metering block
on the choke side just above the idle screw?

I am "testing" a friends 750 who got it from a guy who got it
from...............I might buy it.

Posted By: 05dakota

Re: Holley 750 ?? - 07/05/12 02:13 PM

distributor advance?

Posted By: GoDartGo

Re: Holley 750 ?? - 07/05/12 02:14 PM

I believe that is on the base plate.

Posted By: bigsbigelow

Re: Holley 750 ?? - 07/05/12 03:38 PM

The vac port on the metering block is a "ported vacuum" source. It is where the Mopar brand vacuum advance distributors are supposed to be hooked to.

Posted By: Cab_Burge

Re: Holley 750 ?? - 07/05/12 05:44 PM

Quote:

The vac port on the metering block is a "ported vacuum" source. It is where the Mopar brand vacuum advance distributors are supposed to be hooked to.

If you hook it up to a vacume port on the carb. that is using intake manifold vacume you will have full vacume advance at idle and loose it at WOT

GM did that way for a short while in the 1950s on the V8 Chevys

Posted By: Jerry

Re: Holley 750 ?? - 07/05/12 06:07 PM

if you hook up to manifold vacuum that might not be a bad thing. mopar distributors are horribly over advanced from the factory anyway. you really want to get some lighter springs in there and if you hook up to manifold vacuum you will have your base advance plus canister advance giving you around 15-16 degrees which is good. the while driving you get your base advance plus your plate advance which would put it around 35 degrees