318 Tuning Tips - Help!

You should really use a timing light...but I'd back the timing off a few degrees and test drive it. Have you messed with the acc pump squirter? The squirter cam? Might need a little fine tuning on the squirter and not the jets. I'd up the squirter a size or 2 then try it. Remember anything over .040 on the squirter size and you need the hollow screw. Also to set the PV you need to measure the manifold vacuum with the car idling in gear if it's and auto trans. Then subtract 1.5" from the reading on the gauge to get the PV you need. If it has back fired it's a good chance the PV is toast.