1970 Duster 340 Clone*Update*
The 360 replaced the 340 in 1974, so that Cuda should've been a 340 car unless someone dropped a 360 in it.
I have a 340, BUT had I not got the 340 for next to dirt ($50) and had I known at the time I was looking for a motor about the 360 LA roller block motors I would've gone that route in a second.
You'll find the LA roller motors (360s) in Trucks and Vans, just read the side of the block before you start pulling. Also be on the look out for the "302" casting heads on 318s, people like to buy those.
I can give you the specs of my 340 build if you want that.