380 hp Magnum crate dieseling problem

Like said, check for the throttle blades open too much ="idling on the main circuit " which usually just makes for stink rich idle...but I guess it can also cause run on, but mostly coupled with extra air leaking in..Vacuum leak. As you stated already...the idle mixture screws , double pump as stated so we know there are 4, are only a 1/2-3/4 out...so let's explore the next thing.

If the cylinder psi is in question and carburetor checked to be correctly adjusted..you would approach it by taking some timing out ... or running premium like those motors require....and octane boost ,sometimes.


What is the initial timing/at idle?