81 W-50 Formula
 

With an engine code of W in the VIN, which stands for the 4.9L E/C engine - which motor would that be? Would that be the 2bbl or 4bbl and what is the HP?

I've been offered a low mileage automatic that would be perfect for the kids to drive next summer.

My YO book says: W= 301 ci, 135 hp (or 150 hp T/A4.9) 4-bbl V8
So looks like both were 4 bbl. Both were definitely Electronic Controlled. That's computer timing control and electronic metering on the primary metering rods.
Not much eh
and make sure you're looking at the 8th digit on 81 models
Clay