Looks like a "Truck/Industrial" motor (as in not passenger car/PU)Im not certain but I don't think its as easy as a upper end change over...
Ramchargercentrail For sure it is a truck/industrial 413. I have one that I rebuilt .030" over and put it in a Dakota with the industrial heads and all. I too want to eventually swap over to 452 or 906 heads, but haven't had the time. The 413's are still just an RB block so "normal" heads and water pumps will mount to them. Just be aware that these are low compression motors with dish pistons so putting on 906 heads will lower your compression ratio, that way I wanted to go 452 closed chamber heads to help offset that.
My 413:
