I want to put my 94 t5 into my 87 coupe please help

I seem to remember hearing that the bellhousing is a different size too . . .

yes you need to swap the input shaft and bearing retainer from the fox T5 over to the 1994 T5, then you can use your fox bell housing & driveshaft. The 1994 bell housing is thicker pushing the tranny further back, this stuffs the driveshaft up into the tailshaft housing of the tranny which is no good. I think steeda and other companies make a spacer that goes on the diff, then you could use the 94 bell w/o replacing the input shaft. if it where me I would replace the input shaft/retainer, it's the easiest way to do it. some sources..

Hanlon Motorsports - T5 and Tremec parts, sales and service

Astroperformance.com - Your Manual Drivetrain Specialist

Modern Driveline - T5 / TREMEC TKO Transmission Conversion - 5 speed & 6 speed solutions to swap your Ford Mustang, Falcon, Cobra, Hotrod into Overdrive! Performance Parts