AFAIK, no one here has tried a MAF swap. I would think that a different MAF would confuse the ECU, since most MAF control on early units is at idle and becomes less of a modifier as rpms increase.

I have no idea if the ECU can "learn" anything... I doubt it. I'd think it's only programmed to read signal input and adjust fuel and spark within the imbedded lookup tables. I'm not going to assume the ECU can handle anything over a 15% change from the normal range and have chosen injectors accordingly.

I've run my truck 5000 miles with an analyzer display beside me and can only say that the ignition timing is very much dependant on throttle position and engine loading. At full coast downhill highway speed, advance is 38-40*BTDC and at uphill/full throttle it declines to 15-17*BTDC.

Frank