Thats a powerlock. My red 71 440-6 4-speed cuda had a 410 powerlock. Oct 70 build. On the shaker hoods I am pretty sure they used what they had. Every 71 cuda I ever had with a shaker was a 70 hood. When we had our shop I bought the shaker off of a brown 71 4-speed 383 cuda from texas in the 80s. Not sure on the exact build date but it had billboards, rear window louvers, and the gullwing so not an early car, it was a 1970 hood. Guy needed $$$ to get home but would not sell the car or louvers, wonder if it still exists. On danas my worst example is my 2000 diesel pickup, it has a 1995 date housing with a powerlock, I bought it new and it is untouched. The stuff does sit around, I figure they went to rear disc in 2001 so they used them up, 71 cudas were probably similar, only what about 300 got a dana if that many, from what I am told all 71 e-bodies are traclocks, mine was not. Kinda funny we were just talking about this last month, I sold my 6bbl cuda and told the new owner not to believe everything you hear about 71s.