I don't know what the big problem is here... THE WATER PUMP DETERMINES THE INLET LOCATION! NOT THE TIMING COVER! Yes. I was YELLING. The timing pointers on most Fords were removable, therefore you can just bolt on the one you need. NO BIG DEAL! YOU GUYS ARE MAKING THINGS WAY MORE CONFUSING THAN THEY NEED TO BE!
Actually, there is no place to mount a timing tab on a 289 cover. That's why the timing tab is cast into it.
For a pic of a 70's small block timing pointer that will bolt onto a late 289 cover, see my photobucket pics linked to below. First pic in the album is it.
Compare the casting numbers, those do not lie. The one you claim to be from a 5.0 HO, is one from a 79-85 Mustang, not from a 86-93.
I see the removable timing marker on the left cover, that matches the balancer... I see that it uses the lower two timing cover bolts that are on the 289 cover as well. Transfer the pointer to the 289 cover. It appears it may need to be trimmed slightly to clear the dipstick tube. No biggie. If it is a 5.0 engine, that balancer will have to be used due to the fact that Maverick balancers were never made in the 50 oz flavor.