I need to replace my clutch on my '85 with 460 & T19 and would like to go with a 12" clutch and right now I don't know if it has an 11 or 12. The issues is that I can't have the truck out of service for more than a day.
I was wondering if anyone had a good flywheel they'd be willing to "loan" me.
If it needs it I'll have it surfaced and drilled and tapped to accept a 12" clutch.

Once I have my gearbox removed I'll check mine. If it'll accept a 12" clutch and looks ok I'll just return yours to you. If mine is only drilled for 11" I'll use yours and give you mine, after getting it drilled and tapped if you want and/or resurfaced. I'll also make sure the ring gear is in at least as good condition as yours was.