hello guys,new to this, hope you can help me,tuning problem with a 403 cannot get it to completely stop pigning detonating:1978 403 block bored .030,probe pistons,cam extreme energy 268h-10:268-280,224-230 at .050,485-490,heads 350 big valves ported cfm 217-167,compression 10.2,performer rpm,quadrajet stage 2,proform HEI,compression test 150 to 160 ,running 91oct pump gas, tryed a lot of things ,timing at 25 total with slow curve,

 

What is your static timing?
Did you set the timing with the vacuum advance disconnected and plugged?
Have you checked for vacuum leaks?

 

no vacuum and the timing is initial 14
2000 rpm=23
2500 rpm=26
total timing 26
its the max that it can take

 

no vacuum leak the car runs pretty good till 2500 rpm but doesen't pull any more after that with out pingning !