Terra Nova was really good, it was a golden underdog, missed out due to the Doom hype.
Grand Prix Legends & Nascar Legends. Both produced by Papyrus/Sierra. Both are brilliant sims, GPL was especially demanding on systems back in 1998, wasn't helped that the default car setting was nobbled, so it made it very hard. I tried it not so long ago and its bloody hard, 1967 Monaco with the kerbs and lamp posts.
Historical motor racing sims even to this day have never took off. Even now, there are very few sims based on motorsport from years gone by (Indy, Sportscars, Le Mans, F1, Rally).
You can drive some classic cars in most major sims nowadays, yet many are reliant on the mod community. Most of the classic racing cars you get to drive are racing around modern circuits, where GPL simulated a full season cars and circuits.
Would love a full on sim based on decades where you could race a season from the seventies or for example Group C Sportscars, Group B Rally etc...