Need Help with 94 Mustang

Although i have come here for help with other cars, this is the first time i've come here for one of my own cars.

A week ago i began replacing the engine in my 94 convertible. after some debate me and my brother agreed that we should use an engine from a later model vehicle as the motor would have fewer miles. we found a 98 Mustang, the engine looked almost EXACTLY the same except the motor mounts were slightly different. got it in the car and even the wiring harness fit!. but when everthing was hooked up and we tried to start it, the engine wouldn't fire up! after chasing down the problem we found that the Distributerless Ignition coil wasn't firing. i know for a fact the coil was working because it came off my old engine and it was still able to run, but was about to throw a rod. we've tried changing the Crank and Cam sensors, still no go. My brother says it is the Harmonic Balancer and crankshaft timing teeth causing the problem, but i think differently since it is the one that came with the engine. any help would be greatly appreciated as i need to get this car fixed ASAP as i am tired of riding my Bike and the bus to work!:banghead:

On anothe note, i recently found that when i connect my battery the Tachometer is jumping around, even though the engine isn't being cranked. any Ideas on what's causing that?

Does it start at all couldn't tell if you got it running by your thread, If not the motor needs the 98 computer and possibly wiring harness, even tho it is a 3.8 the motors are built a little differently, I own a 94 3.8 and when I went to swap motors the only one that would work with the 94 computer correctly was the 95 3.8 and that's with having to use the 95 radiator

Naw, got if fixed a long time ago. I did a little back-tracking and found that the connection block for the wiring harness wasn't even connected! I had it running the night after I made that post, so thanks anyway!