I have no knowledge or anything with which to compare different fuels with in regard to older vehicles (pre 1990)
However Just recently I have switched to using exclusively Caltex 95 in all of my vehicles, Mainly because some of them are turboed and the performance (economy )etc when using fuel from the local Gull servo. seemed to be lacking somewhat.
The vehicles, cars and motorcycles, definitely run better when on the Caltex and the fuel economy has definitely improved, so in that regard I am happy to pay the extra few cants per fill up that the Caltex costs.
I also quite regularly add in some F10 fuel additive when I remember, I think that the F10 does help, especially when there are fuel injectors to consider.
Cheers , Winston66, Northampton Western Australia