I always thought this '77 302 was Manifold Vacuum only, and started to set up my new Edelbrock as manifold vacuum, but then I spotted what looks like a PVS switch on the old manifold. I have several questions: 1. Is this a PVS system? 2. Do I have to run it as a PVS, or can I convert to manifold vacuum? ( what's involved?) (is there an advantage to either?) 3. Anybody got a suggestion on how to remove the old one from the old manifold? It won't budge. Can I heat the manifold around it with a propane torch, or will that wreck the switch?
I believe he is talking about vacuum spark advance to the distributor. I think it is ported from the factory, and if I am not mistaken, there was a heat sensor in the system to prevent advance until the vehicle was at operating temp. I just chucked it all and ran ported to my Holley, but I get pinging. I'm gonna disconnect it and recurve the distributor to run just mechanical advance. If you run manifold vacuum to it, you will get full vacuum advance at idle. I can't remember seeing a set up where that was the correct way to do it.
run full manifold vacuum to the trans If auto, and run the ported vacuum to the distributor. on an edelbrock carb the ported vac is the recessed one. looking at the carb from the front, the two front mounting bolts as a reference, you will see left hand ( i think) is further back than the other. run ported directly to dist advance port, unless you want to keep the heat switch. time engine with it unplugged from dist, and plugged off with a golf tee or something. mess with the maverick you get the horns
