starter motor dragging for 4 seconds???

I am a newby to this site - Please empower me with your wisdom oh mighty 5.0 gearheads!!!! I have a 1970 f/b mustang with a 1993 5.0 gt FI engine and a 1989 5spd in it - it is now up and running but there is a problem with the starter - it seems to hang up for a few seconds after the engine is started and it sounds terrible for that time - as if the starter is still engaged but the engine is running then it finally kicks back. The engine SUPPOSEDLY came from a 1993 junk yard 5.0 HO GT mustang w/ a 5 spd but I had to buy another transmission as the original was sold before I got to it. Who knows what the junk yard people did to this motor before I got it - they said it had 93k miles etc... I was able to get all the wires, computer, accessories, etc... when it was delivered. The engine runs great and the started that came on the junk yard motor started it fine but has always hung up - I have changed the started with one from the auto parts store for a 93 gt but it still has the same problem. I have added shims, lubed the drive, test lighted all the solinoid wires to the starter, ignition switch, etc... and the test light goes on when the key is in the start mode and immediatly goes out when the key is released (I had heard somwhere that when you retrofit and use the 93 solinoid instead of the 1970 solinoid on the apron panel that you have to switch a wire around so the starter does not do this but I cannot figure it out) I have also heard that there are 2 different flywheels 164tooth for a/t and 157tooth for a 5spd and there are different starters as well for 1992up and 1991down - could I actually have a 1991 or older motor and be using the newer starter or vice versa and causing this problem? (who knows if the junk yard told me the truth about the year) PLEASE HELP!!!!

methinks I have been blessed with the solution from a fellow Fordahaulic - I have been advised that the 93 mini starter has a built in solinoid that requires the heavy guage wire to go to the battery hot side of the apron mounted solinoid and the skinny wire from the starter needs to run to the "switched" side of the solinoid otherwise this dragging will result. He futher stated that the 91 and older starter would be a direct bolt in that would not have the built in solinoid and I could just use the heavy guage wire on the "switched" terminal on the apron mounted solinoid. I will have to check this out to let you know in another post after I have a chance to get to it.

I did the thick/thin wire switch on the solinoid and it now it works perfectly! - I'm told this is a common problem when people install new solinoids because it does not make sense to install the heavy wire on the same side as the positive battery cable connection ....