No way, no how, would I have my suspension brackets welded to cast...but thats just me. Use the 9" you have, or if it must be a Mopar rear, use an 8.75.

Look at it this way...axles are axles, brakes are brakes, spools, gears, etc..they cost the same for either rear. You have the 9". Yes, you will need to buy a decent center and an alum pinion support for the Ford. Both of these will cost you about $500 if you shop around, but you won't have your main suspension components welded to cast.

Monte