[Pdstark]

When I replaced the head gasket’s and water pumps on my stock ‘51 F1 flathead (with 8ba stamped on the heads by-the-way) I used compressed air and a shop vac to remove the accumulation of rust pieces and left behind sand from the block. It was an arduous task but I believe I was successful in removing nearly all of it because cooling system is working great with the temp on both sides now (nearly) identical (180degrees) and stays at temp under load - even when temp outside is over 100. I use distilled water with inhibitor. I know it’s not the same as your A but thought I’d share my experience.