Tuning 318 with HEI

I have a 86 dodge truck with a 318 stock except for a 500 holley 2 barrel carb and a converted gm hei distributor and dual exhaust with new cats and flowmasters. Can anybody tell me how to tune this setup? I am getting some part throttle pinging and need to know how eliminate it as I am trying to tune this thing for some decent power and milage. I did see a post on using magnum heads on these earlier 318's. Would that give me better milage along with better performance. I run coast to coast with this truck a couple times a year. Thanks in advance for any help. RD

a converted hei ,was the timing curve played with??. maybe too much advance somewhere ?
i helped a buddie fix a 430 buick he had swapped into his 76 riv once. he had used the original 455s hei and was having ping trubile at cruising speeds. we went and got a adjustable vacume advance for the hei and fiddeled with it a bit and it solved the problem.
where did you get the hei conversion?? its a neat idea.

I got the converted hei off ebay. I had to custumize the firewall alittle to install it. It fits in very well. It fired right up when I turned the ignition. Although mine was a home made hei converted distibutor you can purchase them new at davis unified ignition or (DUI) for any make or engine including ford. I like the performance and simplicity of the hei's. I just took the truck out for a run after relacing the springs and weights and ended up getting rid of the pinging by setting the initial timming at 5 degees and ended up with total advance of 42 with no pinging. As you suggested I will try a adjustable vacume advance. Thanks for the reply.