[roger1]

Originally Posted by dataway

Not sure about the GP part, but the A body case has a dish in the passage from the blower to evap to clear the wheel well I think. Seems like a "taller" case would need even more of a dish in it. Although it's a modification that probably wouldn't be too hard to make.

I managed to find a Grand Prix evap box at a super good price so I bought it just to see how it would fit.
You were right Johnny, it would need modifications to fit a GTO. It bolts to the firewall perfectly but there's not enough clearance to the inner fender without that relief that the stock box has. I really don't want to spend the time it would take to do the modification so I am just going to go with the Astro Van motor like you did.

The seller also sent the squirrel cage fan with the box and it's a metal one in extremely good condition. Also the motor cooling hose and it's in really good condition as well. I will sell it all to anyone here for the same price I paid ($35+shipping) that may want to take the time it would take to do the modification. If anyone here is interested, let me know and I will post a couple photos of the parts.