This is how I approach many frames without forks now. Find a 1" threadless fork or even tall 1" threaded forks (but do not clamp on threads), order a 1" threadless headset and shim, use modern stem of choice.

One of my favorite builds is this 1984 Bianchi San Remo. I bought the frame alone at a swap meet and had the fork from a tall scrapped 1981 Puch Pathfinder. The color was close to identical and I had enough space for the threadless headset and stem after removing the threaded portion of the fork.