Help with 64 Barracuda

I have a center section in the attic. I can check on the condition and report back. Let me know if you are interested. The fender is a ONE year only part. Lucky for you there were a LOT of Valiants built in 64. The Valiant and Barracuda use the same fender.
The rear axle: Any A body axle will fit any A body car. The chassis did get wider in 1967 but most of the suspension parts will interchange. The price of an 8 3/4" can be pretty stiff. I'm talking $500 for a well used setup needing brakes, brake lines, maybe even gears and axle bearings. I have seen 67-72 8 3/4" axles go for close to $1000 when fitted with rebuilt 10: brakes, a 3.55 gear and a LSD.
A cheaper option is the 8 1/4" axle. These came in 73-76 A body cars and fit all the way back to 1963 models. They are very tough but the one thing that may be a drawback to you: They ALL used the larger bolt pattern wheel like the Charger, Challenger, Monaco, etc.