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Jacfourteen · 11-23-2011, 03:14 AM

There is lots of debate about the full vac vs. timed vac ports for dizzy advance, but for a performance application the full vac is much better. This way it is advanced during low load cruising, and backs off the advance when load increases and there is increased chance of detonation. As a side benefit it also allows a smother idle and lower idle temperatures. Timed vacuum was just a band-aid fix to lower emissions at idle.

11-23-2011, 03:14 AM	#21
Jacfourteen Big Red - Now its a SWB! Join Date: Jun 2009 Location: Oroville, Ca Posts: 1,624	Re: Truck won't start right up and backfires like crazy! There is lots of debate about the full vac vs. timed vac ports for dizzy advance, but for a performance application the full vac is much better. This way it is advanced during low load cruising, and backs off the advance when load increases and there is increased chance of detonation. As a side benefit it also allows a smother idle and lower idle temperatures. Timed vacuum was just a band-aid fix to lower emissions at idle. __________________ 68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread 41 3/4 ton (wife's)-flatbed, fully restored to original 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's