Are you talking about the actual rubber engine mounts or the engine mount brackets?
For a factory big block A-Body the rubber mounts are the same but the drivers side mount bracket is different between a 383 and a 440.
The 383 mount bracket attaches to one front mount ear on the block and has 2 bolts that attach to the front of the block in front of the number 1 cylinder (above the oil pump on special bosses).
A pic of a 383 mount.
The 440 attaches on one front mount ear and has the other 2 bolts attach on the front of the pad that the oil pump bolts to on the block.
I tried finding a pic online for one but haven't found one yet.
I've got one of each out in the garage, I'll try to find time to take a pic.
Essentially it has another bracket welded on to the 383 style mount that goes down and attaches by the oil pump.
Copied from another post about the mounts.
ok 1967 383 A-body used 1 K-frame, 1968-1969 383 and 1969 440 A-body used 1(SAME) K-frame. the rubber motor mount insulator for the passenger side are the same, 1967-1968-1969 383 and 1969 440. the passenger side steel engine mounting bracket which bolts to the ears of the engine block are the same, 1967-1968-1969 383 and 1969 440 A-bodies.
the drivers side rubber motor mount insulator is the same 1967-1968-1969 383 and 1969 440. the drivers side steel engine mounting bracket is the same for 1967-1968-1969 383s. the 1969 440 A-body used the 383 bracket with an additional piece of steel welded to the bracket and had holes drilled in it to attach to the 440 engine block.the 68 GSS Mr Norms 440 cars used the 383 components with added drivers side additional bracket attached. and yes i have parted out 383 A-bodies, and owned a 440 Dart.
