ok, I am an amateur hobbiest trying to figure my way through tuning my 302 driveline specs are 302, gt40p heads Lift: .498''/.498'' Duration @ .050: 220°/220° Advertised Duration: 282°/282° Camshaft. 600 cfm Holley, c4 after putting a new carb on the engine I noticed some loud popping comping under deceleration. it still has a miss to the engine under acceleration but the new carb fixed the off idle bog (huge bog that lasted until about 3 grand) I retarded the timing a tiny bit this am and now the car does not pop through the exhaust but will die at about 4 grand for a few seconds, then come back strong. I am getting worried about detention damage. I am also out of ideas. where should I look? what is the next step? Thoughts?
Need to baseline the tuneup and check overall engine condition with a compression check. This includes noting the current carb calibration(front and rear jets, power valve, pump discharge nozzle size/accelerator pump cam, etc.. and verifying timing advance curve with a light. The fact that retarded timing helped cure popping sounds indicates one of two possibilities. The carb is entirely too lean.. many potential causes aside from simple main jet changes.. or.. the timing curve is far too aggressive for the current fuel curve and octane rating.
