Scraping noise from engine

[rivcokid]

Hi all - when I start up my 1931 roadster, I hear a very audible noise that I can only describe as a scraping noise coming from the engine. It is cyclical and does not increase/decrease with engine rpm. There is no effect on performance, and after a few minutes it goes away and the engine sounds fine. I may not be doing the description of the noise much justice, but that's kind of what it sounds like. Any ideas? Thanks in advance!