I have 305 newly rebuilt with a 600cfm holley with electric choke and vacuum secondary. The car ia hard starting when it finally decides to run after warmed up the idle will surge slightly. I have adjusted the fuel bowls have the distributor advance 10 degrees new wires, cap and rotor and pickup. new fuel filter runs great when ya get on it runs like **** at idle rather lopey for a slighty more than stock cam. It will rev high and when it comes down off a high rev she will pop in the exhaust but not to bad. I have manifold vacuum at 13-14 so I am kinda lost here on this.

 

13-14 is low for a "slightly" more than stock cam, altho that is a little vaugue. I suspect a leak of some sort.

Try this, close the idle mix screws and see if it still idles.
If it stalls like it should, put them back where they were and try closing the idle speed screw, see if it stays running or not.

 

I'll give you a little trick to try ...BUT do this at your own risk think about how you do this and what not to do... to prevent yourself from being blown up!

ok go to wal-mart or any hardware store and get a propane torch ..now unscrew the tip off the torch and slip a peice of rubber hose on the end long enough so you can move it around the engine ..turn on the gas and run it over the intake maifolds edges etc. etc. anywhere there is intake vacume run it over it (except the vacume advance on the distributor there are sparks in there! dunno if you have that or not ..but just in case) while your doing this listen to the engine closely if there is a change in idle then you found your leaK (idle will become slower and ruffer) Good luck!!!!

 

I pulled 4 plugs and they were black with a slight odor of gas. Could this be my problem? I think it is the choke but I am not sure of the steps to set the choke? Could you help please? I didnt find a vacuum leak I did find some corrosion around the power valve which is a 6.5 with 65 jets. The powervalve was dry I am not sure if it was good or not. Thanks for any help here