timing baselines for a 521 efi

i am trying to adjust the timing on my efi521. i am wondering what the timing should be without the spout and with the spout. i am running 92 octane and around 10.5-1 comp. the engine is efi with a modified 5.0 a9L computer. it seems like if i set it at around 12 without out the spout and then it goes to 32 with the spout, and it runs like crap. if i set it around 16 -18 without the spout and then it goes to 39 with the spout, and runs a lot better, it really revs up quick. i have seen it go as high as 50 with the spout installed, while i was adjusting it.

what should be a good baseline? also i am setting the timing at idle around 1000rpm. should i set it at around 2000rpm idle? whats a good baseline? i know at 39 i can not hear any pinging or detonation. i am not really able to drive the car as much a i would like to. right now i found several exhaust leaks and also found out that one muffler is spaced about 18 inches farther back down the exhaust system than the other, i do not know why because there is nothin blocking it. i plan to install the mufflers about 16 inches behind the header flange and turn down after the muffler. it is all 3 inch with hooker aerochamber mufflers. maybe after the exhaust is straightened out it would be easier to hear any pinging.

any thoughts on this?

I'd say 12 to 16 initial, possibly a bit more if it has a big cam in it, and 36ish total in by 3000 when quick revving it should be a safe baseline. The efi computer will attempt to give it more timing at higher rpms for part throttle cruise condiditons. What I mean is, it is not uncommon to see timing well into the 40's while holding steady rpm at say 2600. But when you mat it, a proper tune should jump on your WOT programmed timing curve and advance to the 36ish you have for total. That was my experiebce tuning in a F.A.S.T. on my own previous ride and looking at others' tunes.

I currently also have a blown 4.6l in a 2008 stang. When I hook up my SCT tool it does exactly what I described. Kinda scary seeing 45 degrees at part throttle (0 boost) but that is how it is.