You should also ad yourself to this BB
http://www.nastyz28.com/forum/index.php
No the crackle is not normal. Set your total advance @ 38* at 3000 rpm with the vacuum disconnected at the dist, If it pings at WOT then back off to 36* etc until the ping goes away. I gather your 780 carb is set up, floats, mixture screws, sec throttle stop screw setting, correct power valve, accel pump cam position, accel pump .015 setting at WOT. Jets should be 70 for prim and 76 in the rear. Solids set at 24I/30E.