Steve if you are truley looking for smoooother performance out of your 440---put in a billet mechanical advance distributor(MSD). Unfortunately it won't look Original--but it will run better all the way around. The cap on the factory units put the spark towers close together allowing for arching and the vaccum advance seldom provides the correct adjustment for todays fuel. I bought a brand new crate hemi and messed with the jets and timing for a week before I found out the vaccum advance wasn't working properly. I've owned alot of big-blocks in 35 years of driving & racing--with alot of different cam & intake combos--but the ONE THING that made ALL my MOPAR engines run better was the distributor swap--better spark and smoother timing adjustments. Hope this helps