Ross/Kzoo
The only book that I had growing up as a teenager, and working on my Dad's '31 CC Pickup, in the '70s was:
Model A Ford: Construction, Operation, Repair for the Restorer written by
Victor W. Page
Therefore, I believe that I read about the basic procedure in his book. It described using Fine Threaded Brass Rod. I went to the hardware store and couldn't find brass rod in fine thread, but I found 1/8" Solid Brass Pipe Plugs. I thought that this would work better anyway because of the fine thread and the taper of the plug.
I started by drill stopping each end of the crack. I then drilled and tapped the first hole on either end of the crack, I ground down the end of the tap so that I wouldn't run into anything in the water jacket and I could obtain just the right depth and tightness (not to tight, not to loose) on the Brass Plug. I then ground each plug near flush with the block, I drilled half into the first plug/half into the crack, drilled, tapped, plugged, ground and worked from both sides towards the middle. It almost looks like solid brass when finished.
I center punched each plug to expand/set them firmly, ground down the plugs about flush with the block.
I then painted the block with a polyurethane paint that I mixed up.
I had overheated this engine about 25 years later and blew a head gasket when I first put it in my Phaeton and it had developed a slight tick that only I seemed to be able to hear. When I took it out I found a scored piston, I filed down the score marks, honed and deglazed the cylinder, re-ringed it .020, the rods had been eaten away from the Antifreeze during overheating, STD Size, I bought a set off Ebay for $101.00 installed them and it runs extremely well and I have put many thousands of miles on this engine.
I wanted to show the repair to a friend, who actually thought I was crazy when he saw me do this originally, because he had bought a quite expensive H and H engine that had a rusted out/poor casting at the rear water jacket about where the throttle linkage mounts. Thankfully we ran his engine on a test stand and found the leak before he installed it in his car. We repaired it with a half dozen pipe plugs using the same procedure.
It is a Diamond B engine I took out of a '32 BB, put it in a '31 CCPU I built from parts, later installed it in my '31 AA, then into my Dad's '31 PU, and it currently resides in my '30 Phaeton.
Hope this helps,
Darryl in Fairbanks