well, first of all GPL/GPLEA car stuff cant be converted into any other game sim as easy as people thinks. its basically impossible, because plenty of the GPL car parts are simple flat 2D objects, including a whole virtual cockpit. the whole ingame magic is because of great looking textures there. that means a lot of parts must be modelled newly for other sims.
just forget someone will convert the GPLEA GPL cars into modern sims "properly" in future. we may use his textures, and a few 3d parts as templates / blueprints, but the rest would be a pure scratch work.
basically this mainly caused the (un)popular SlimJims F1 Classics mod, which is GPLEA stuff conversion, looked so badly. a lot of 3d parts and textures was created newly, but in a very very poor quality. no wonder GPLEA never gave to SlimJim permissions.
all next SlimJim mod source overhauls during times added some kind of improvements there or here, but to be honest, it was always a big tragedy... up to the Assetto Corsa payware F1 Classics conversion / rip by the russian team, which was just another kind of overhaul of the ripped SlimJims mod souce together with the other moddder team improvement attempts, but this time the team got some better 3d artist. finally. be as be, it still is a payware with a ripped content from free mods.
Bazza did for the AC mod his various patches related to physics and maybe to sounds. linking to other web sites isnt allowed at this forums, so no link, sorry
the reason why the SlimJim mod still is converted over and over into various sims is simple:
there doesnt exists any other complete F1 1967 season grid sofar...
... well, actually one such exists and it is a fully free add-on, try google for "F1 LEGENDS RACING mod" or
check this thread.
now just needs to hook someone for AC conversion. two year old sample image here: