adapter plate? centr-o-cast

[chopped and channeled]

Hi everyone, bought a truckload of hemi stuff and in the mix was a centr-o-cast aluminum plate about 5/8 inch thick or co #1736183 any body know what this is holes line up with back of hemi block, also a four barrel intake with numbers 1731703-2 doesnt show up anywhere I've looked it is cast iron ...thanx Scotts Hot Rods

[TrWaters]

If you have a 1736183 thats 5/8" thick, then it sounds like someone has had it in a milling machine. These plate were used in 57 and 58 applications, are are approximately 1.125" thick.
The 1731703 intake was used in 57-58 also, 354 and 392