I use a 3550 transmission. It's an excellent piece. Your current transmission uses a 10 spline input shaft, so it will the be the same. I snapped the input shaft in two once, but I have like 630 ft./lbs of torque. You will have to modify the crossmember, because it's shorter than the T-5 in the SN. You will also need a spacer for the driveshaft to make up for the fact that the transmission is 5/8" shorter. You will need a Foxbody clutch fork. Also, the hangers that hold up the H-pipe will not work. You will have to leave them off, or make your own brackets. The 26 spline upgrade is only like $128. If you are going to buy a new clutch anyway, now is the time to upgrade, because you will need a 26 spline clutch disk o go with it. They don't make a bellhousing for the 3550 that uses your clutch fork, so they are labeled as Foxbody bellhousings.
Kurt