Gonna feel dumb on this one I think, but since I really am not sure, here goes...

I have a 69 Barracuda with a locked up junk 318. Looking for a donor motor, but here is what I don't know...will any 318 drop in? Truck? RV? Any year? I have a 7 1/4 rear end, so am afraid to go with anything bigger. I can find trucks with good 318's all over the place so this is why I am asking. Thanks for the help...

Dave in Colorado