One caveat is that vintage events in the US only consider engines and chassis that are older than 30 years…. So you can’t quite run 90’s engines yet, or at least you’ll have talk with the organizer beforehand.
For Super National we listed eligible engines to make things easier. There was quite a few. Easier if you have access to homologaiton documents. The FIA used to literally release a book with all the engines homologated during a particular homologation year. Sometimes there’s extensions and anomalies that can throw you off in terms of identification. I am not an expert for identification though.
That looks like Parilla TT36, which is 1989 File:Pag 10.jpg - Kart Wiki this website has a few engines on there. Nice carb with it too.
All vintage series have different classes for different eras. This engine would be legal in classes considered as Pre-92