I did some digging before I bought it. I can’t speak to the production numbers, but here’s the history.
the Motorsport speedo follows what was used in SSP cars. In 87- early 89, the SsP cars used the 140mph certified calibration speedo. Since Ford already made the part, they slapped a Motorsport logo on the face and sold it to mustang folk stuck with the dreary 85mph speedo. I imagine it was a desirable swap those years.
in late 89, the 140 mph speedo came out. The SSP cars went to a 160mph speedo. Ford sold it as a Motorcraft version as well. One year only fit on this part, so I think the ‘89 SSP speedo and the ‘89 Motorcraft 160 were the rarest for this year only.
for 90-93, the SSP was 160mph, and so was the Motorcraft unit.
Motorcraft speedo units:
87-early89: 140mph E7ZM-17A277
Late 89: 160mph E8ZM-17A277
90-93: 160.
For SSP
87-early89: 140 mph E7ZV-17A277
Late 89: 160mph
90-93: 160mph E9ZV-17A277
weird thing is I’ve seen tons of the 87-89 140mph units and tried to buy a few here and there. I knew there was a 89 160unit, but never saw them for sale. I have not seen pics of a 90-93 160mph speedo. I think a few guys here have them though. I’ve actually seen way more of the 140mph speedos for sale, vs the later 160mph units. I would imagine the desire to go from 140 to 160 isn’t as great as the desire to go from 85 to 140, so perhaps more 140mph units were sold.
searching ebay...not finding any 90-93 Motorcraft ones. Just SSP units. Saw a post where someone said you snap off one corner of the 89 version and it fits the later cluster. I can’t confirm until part in hand.