R&MCM has a 4 cylinder distributor & two headers. i think if anyone is building a car which would use a 4 cylinder engine, a lot of the R&M parts would be useful.
EDIT: the HAMB 1:1 forum has a 4 banger monthly thread which is helpful for research - Technical - ***June 2025 Banger Meet Thread - A Change in the Weather*** | The H.A.M.B.