I have a 1953 263 that I bought recently. When I opened the coolant block drain petcock, nothing came out. I removed the petcock and stick a screwdriver in the hole and it only went in about 1/2 inch, with black stuff in there that I chiseled at that was hard as a rock and got the screwdriver to go in an inch - I can chisel away more at it, but this only cleans it out by the petcock mounting hole. On the non-rebuildable engine I'm replacing, the same screwdriver easily goes in the petcock hole up to the handle without hitting anything - 4 or 5 inches. I'd like thoughts on how to clean out this hard sediment at the bottom of the engine block's water-jacket. I don't want to take it to a shop to be boiled out. It has not been put in the car yet. Should I pop out the frost plugs to gain more access?....or is there an easier way?
Dave
Dave