Cbystrack

i just bought a new holley carburetor because my last one was junk, anywho the new one has vac control secondaries and i have an hei dist with a vac advance block off......... what do i hook it to now? sorry if this is a dumb question but im lost at the moment... thanks - Chris

ZZ

Not sure what you are asking, but I'll take a stab at this. If you are reffering to the vacuum signal for the secondaries, that is supplied internally. Just bolt it to the intake and you are done. If you are asking where to hook the vacuum advance, you can either use manifold vacuum, or the timed spark port on the passenger side of the primary metering block. I prefer manifold vacuum on a SBC. The timed spark only gives advance after the throttle opens some, then drops at full throttle. Manifold vacuum is present at idle where you need more advance to run a little smoother and cooler without moving mechanical advance, and also drops at full throttle. The timed spark doesn't give advance at idle. Don't know if this helps or not.

Cbystrack

zz, you answered my question in full. thank you very much!