I don't think Goodwood will be worried if a car is Gp1 or one of the other, as long as it is running as it did in period. More of a concern for the
series that some cars will (hopefully) migrate to!
I would love to know what the relevant BSCC rules were precisely. When the championship went to Gp1 in 1974 it was (according to Graham Robson's text am reading) to FIA rules, but then this is contradicted by the fact that it was apparently nicknamed Gp1 1/2 by some journalists right from the start.....
As said and to be expected from them, Ford homologated new parts for the Capri (and RS2000) as required all the way though to late 70s, but Robson suggests that in 1977 the "RAC MSA's rather special and relaxed attitude to it's own Gp1 1/2 regulations allowed the Dolomite Sprints to use twin dual-choke Weber carburettors , a close ratio gearbox and bigger ventilated disc brakes, while the Capris could use a new front spoiler, quick rack and anti-dive front suspension kit".
Now, I would have thought that some of those mods were homologated by the manufacturers, but am happy to be corrected as have not got papers for either. For 1980 the MSA raised
their minimum class weight limits (not FIA's) and allowed cars up to 3500cc. Suddenly the 3528cc SD1 became catalogued as 3492cc- The reverse of Ford with RS1600 when it's 1598cc engine was listed as 1601cc years before!
