early waterpump on 1985 318

(1) bolt the pump on & if the mounting bolt flanges are significantly thinner or thicker than the alum pump flanges are then get different bolts out of your stash. It ain't a super critical deal tho people have cracked the DR #1 cyl wall (it's closest) by using a bolt way too long. Just keep that in mind as you mockup. (2) then bolt on your current WP pulley & measure how much addition pulley depth you need so the groove is back in line with the crank/alt pulleys. You can space the crank pulley out & Mancini has tailor made spacers for that and you can manipulate the alt pulley fore/aft position some. Mockup & go from there. I may have a pulley that will fit! You measure OD & that can be anywhere within reason if your crank pulley will still fit but the total depth is the critical dimention