My rig(01 blazer) had a 1TAD 4l60e with the 300mm shaft, I bought one but its 3TAD 4l60e 298mm shaft. Is it usable? Or do I need a different one?

 

Supposedly the bellhousing for 300mm is 0.4" longer. If so, you would need to use the 298mm converter and work the difference out with spacers or custom flex plate. Also make sure torque converter fits crankshaft.

Thought 2001 S10 had 298mm shaft but I'm no expert on that.

Good luck