I'm just getting into the whole EFI world. playing with a new to me 98 Dakota with an EFI 5.2L that's got some light mods (cam, intake, headers)

I'm working with an SCT engine tuner who will write custom engine tunes for the computer, using a data logger and O2 sensors to dial in the tune.

assuming that it's possible, I'd like to throw as much timing and fuel at it as possible during WOT, but cut way back at part throttle cruise.

I know that at max power you want a ballpark of 12-13:1 AFRs

but what about economy cruise? how much timing is ok, and how lean can you go? I'm thinking that if he can program it, I'd like to see as much as 50 degrees advance at part throttle cruise, and maybe as lean as high 14, low 15 to 1 on the AFRs.

how much advance do the vacuum advances give on the old engines? if you're running 36-38 degrees mechanical all in by 2500, and the vacuum advance is hooked up, how much is the total timing under part throttle cruise?

and how lean can you realistically go without hurting anything, when under part throttle and light loads?