[Flathead Fever]

I wouldn't mess with the studs. From what I understand they were an "interference thread" to prevent coolant leakage. the studs have a slightly different thread than the blocks and this is what makes a nice tight seal. If you run a tap in the block and install new modern studs, you risk having coolant leaks. I know several people that installed new studs and then ended up with coolant seeping up through the threads.

I have about every factory flathead book made and I have not seen anything mentioning the interference fit on the studs, but I've seen several people mention it. The first flathead I rebuilt I ran a tap down through the block. I had to install longer studs because of aftermarket heads. I put sealer on the threads and severalt of them ended up leaking. Lator I watched a factory video of them installing the studs on the assembly line and it didn't look like they used any sealant. So, the interference thread makes since.