if it is a cleveland, it will have a thermostat hole next to the dizzy on the block. The casting on the block will also be noticeably different from a 289 or 302 block. the timing cover on a cleveland is just a metal cover unlike a windsor which is much bulkier. there will also be 4 water passage holes on a cleveland block on the deck surface because there is no coolant passages going thru the intake manifold.