I've read, no first hand experience, is that the EEC speed density ECU's have trouble with cam changes.
The ECU has issues with the change in manifold pressures (when compared to stock).

MAF systems handle cam changes a bit better because it's reading mass air flow vs. intake pressure to run it's calculation.

I thought all 89's had MAF and it was 88 where CA cars got MAF.

 

I’ll correct that - I was a year off with the MAF intro!

 

There were (are) some cams that the SD did OK with, but they are all pretty "small".
I was running on the factory SD in my Mark VII, had AFR 165s, Trick Flow intake (later the tubular GT40) headers, larger TB and for a while 1.7 "Cobra" roller rockers.
I swapped to Mass air and when I did I bought a new Pro-M meter for 24 lb injectors and a set of 24 lb injectors.
Ran perfect.
A few months later I dropped in an XE270HR-14 Comp Cams and it ran great.
Basically, Mass Air can and will compensate and run great with mild(ish) changes/parts.

 

The factory speed density can run with aftermarket cams, just have to keep in mind the processor is dependent upon vacuum to interpret how much fuel the engine needs. With a low vacuum signal the processor thinks the fuel demand is higher.
I run a VM1 on mine, that and the VR1 seemed to work better than the DB1, which worked better than the DA1. I had a B cam in it for awhile and tuned via quarterhorse. The car ran and got down the street just fine, but wasn't ideal. Ideally you could run a stock or similar to stock cam and just use good induction and exhaust. I think mine mad around 320-330 RWHP with similar torque numbers, that's with ported TW heads, ported Vic jr intake with a 4hole throttle body, 1 3/4"longtubes, and 3" exhaust.

 

I got my SD ECU to run rather well with a few mods like Cobra intake, exhaust, larger TB, pullies. Ran very well...but before I cam swapped I converted to mass air and ran an A9L.

 

Pretty much anything that affects the map sensor. When I had a Vortech on my Lincoln with speed density, I had to put a check ball in line so it wouldn’t see boost.

 

Lots of first hand experience with custom tuning the factory '86-88 SD with healthy, tight cams, and I can definitely say Mass Air is WAY BETTER.

 

Yep, easier to tune as well.

 

Nope, ran an E cam with SD for a while. To get it to idle had play with timing and run fuel pressure too high. Ran pig rich, eyes would water. Swapped to MAF and has run much better ever since swapped cams , supercharged, still runs pretty good. I run 30# injectors and an FMU and locked timing at around 20 total. Runs great with 1 exception when I kick on A/C at idle sometime it surges

 

I ran a DA1 on my '86 after a head, intake, TB and header swap. Worked better than the stock ECU. No experiance with a cam swap.

 

My 88 SD GT ran great with the stock Sd cam even with F/S GT40P heads, a ported Explorer intake and Mac P headers. Then, I wiped out that cam when a dog bone jumped. I degree'd that SD cam carefully at 219/212.5 @ .050" lift with lsa @ 112.5 . When I replaced it with a billet Crower 15511 cam (218/224 114 lsa) I traded for, it ran well, but at idle the SD EEC ran too rich and would burn my eyes so I swapped to MAF. Cams looked "close" on paper, but the EEC did not like the change.