I am sure I know what the answer is, but want to double check. I am replacing the 3 x2's with a Edelbrock. Previously I did not run vacuum to the distributor - 57 and later type - but I am going to hook it up to this carb. The instructions say one side is for "timed" vacuum and the other is for "full" vacuum. Which one should I use? Thanks

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Timed.  Sometimes also referred to as ported.

Ron Grove

Wauconda, IL

I'd say try them both - whatever works best for you is the way to go. That's what the Holley tech reps used to recommend. The fact is you can successfully tune the engine to use either scheme.

The "ported" vacuum will let your engine sit there and idle at a somewhat retarded advance setting - raising the water temperature (and exhaust thumping nicely). Running the idle advance on manifold vacuum will lean it out and raise the idle speed slightly - and cool off the water temp a bit too.  

 
 Steve Metzger       Tucson, Arizona