I just knew I would get a wise answer! The thing is in beautiful shape, the seller had no idea what it is for, and I snagged it for 80 bucks... It's always to your advantage at a swap when the seller asks YOU for information on his parts. Play stupid, and bid low! Visibly, I see no differences, and extra umph is always welcome on a big old Buick. I'll check hight differences - I never thought of that possibility, but it explains why my '55 aircleaner is a good bit high off the front mount on the thermostat housing. Lamar, you the man!