help quick, 93 starter in 87GT problems

[fiveohpatrol]

me and a friend put in a 92 5.0 starter in his 87GT today and couldnt find anyplace that carried the cable that goes from the solenoid to the starter so we looked at a 93 mustang and saw how the cable was ran, we basically just ran another wire from the solenoid to the small connection on the new 93 starter, it seemed to work fine, but something isnt right, it starts fine but the starter wont disengage from the flywheel nearly as soon as it should, it sounds like the key is being held in for a few seconds AFTER the car is already started, why is it doing this? is it the way we wired it and its sending too much juice for too long to the starter? anyone here put the new starter on their car? thanks for the help

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88 Notch, 3.73's, Ported E7's, Explorer int. w/ ported lower, pulleys, 1.7RR's, BBK headers, off-road H-pipe, flowmasters, subframe connectors, 65mm TB, shift kit, March ram air ,MSD coil, U/L control arms, 155lph fuel pump, cheap 2800 stall, Crane Adj.FPR, best 1/4--> 13.77@101.35