cobra427mnsi - I guess I should have been more clear or seperated the two comments. Everything you said is correct, but there are tweaks you can do for driveability and piles of initial timing isnt always the right answer
1 - I dont think he has enough total timing, so easiest fix is to crank up initial. The problem is lots of initial on a low rpm / high load it may ping a smidge, like easing off a stop light, where a lower initial with a quick curve may not because its not yet in the curve
2- A better fix would be to build a curve that comes in quick enough to give him 38 or so all in by 2500-2700, with an initial a little lower. I like 14 or so max on the street with 38 total on an FE
A lower initial makes a cleaner idle, better smog (to a point), although I know it doesnt apply, when you sit at a light with 20+ initial, it can get smelly, combustion temperatures are lower and often you can mistake a low combustion temp for a mixture problem.
I am not sure if you guys do smog, and I cant imagine for any Cobra guy its a big deal, but they do burn cleaner at idle with the timing pulled back, cleaner sidepipes, fenders, (bumpers in my case with a Mustang). Notice I didnt say "run better" because advance is good, but looking at hydrocarbons and using a calibrated nose LOL I dont like to go above 15-ish on something that idles a lot
Matter of fact, I have seen a few, mine included, that I was considering changing the idle air bleeds in the Holley when in fact pulling 3 degrees initial out and putting it back in the centrifugal to quickly come in off idle got it to idle much less smelly
You can chase idle mixture, but a street motor likes some residual heat, and running reasonable initial (IMHO 10-14) gives enough performance and allows that heat to help at idle, where advancing it at initial lowers EGT to the point you'll get some stink
A race car is different, lock it at 38 and retard to start, but that motor would launch at 4500 and never drop below anyway