10.5" flywheel for a slant 6?

If it's a SL6 flywheel and 130 teeth I agree with others that it's out of a truck that had the granny gear four speed behind the slant as others have stated. I've never seen a SL6 OD with anything other than a 122 tooth flywheel regardless of the body/year it was installed in. And every V8 OD vehicle I've ever seen had the 130 tooth flywheel installed. As another poster suggested there are a few 143 tooth SL6 flywheels that were delivered as upgrades in trucks with the NP435 granny gear 4 spd. trans. I run the 143 tooth/11" clutch in my 170 CID drag car as the increased mass helps keep the RPM's up when I launch on slicks. When first put together it had an 8lb. aluminum flywheel and would bog/nose over big time when launched on the slicks.