like i said i dont have a pic but i know that the oil pressure sender port beside distributor on back of top if motor is drilled all the way thru to rear main and intersects the channel above the oil filter.. the plug is put in thru the block on the bottom under the rear main and is inserted past the channel to the oil filter. it diverts the oil pressure up to the central oil gallery instead of bleeding most of the oil volume back to the pan.. had a friend who ruined 2 motors thinking he had good oil pressure on guage it must be ok after doing 2nd motor in he took it to a different machine shop who noticed problem right away.. if you have another small block setting around pull the oil pressure sending unit out and insert a skinny screwdriver and take a rough measurement then check your measurement while still in car ... if measurement is different you will know your problem