Greetings, I am manche an di accumulated some experince making 3d meshes in the VR world of second life, I always liked this game and I will be getting this game (not a matter of if but when), I would like to try to model a vintage racecar using one of 2 of the oldest vanilla cars as a source to make a 2 seater racing car plan would include: trashing all the bodywork, use the frame if the vehicle have any, otherwise make one from scratch push the engine location back to create a front-mid engine, use the suspension steering, and engines from the selected donor car hopping up the engine if need to AND sleek streamlined bodywork reminiscent of 1950s-60s racecars
Honestly, none of these vehicles would be an accurate base for a vintage racecar. But if you need to, use the Miramar and build something like the Alfa Romeo Giulia TZ2/TVR Vixen/1600M.
exmaple of a 1950s racecar made with american car parts, old yeller in thsi case notice the pushed back buick V8
This is a very neat idea, but I have to ask: do you know what you're getting into? You'll need quite a bit of 3D modelling/texturing experience, plus a decent level of understanding of jbeam. There aren't a lot of car mods on this forum because it's actually a large amount of work. It takes even the developers a few months to make just one car, going from bodyshell in a 3D modelling program to driveable complete car ingame. Whether you're planning to use many of the assets in the game already (wheels, engines, frames, etc) still doesn't allow for a shortcoming in the above mentioned required skills. Now, I say this not to discourage you nor insinuate that you lack the skill, I just don't want you to be unprepared for the work that goes into making a mod like you have proposed. There is a wiki, which provides much of the needed information to get you started on your way: (http://wiki.beamng.com/) plus the forum here will help you if you encounter any major issues.
modeling is fine, I have made a complete car from the ground up before, scripting and J beaming scares me still http://sta.sh/218jt7c2mwc0?edit=1 http://sta.sh/0cpi5sjx652 I even made (mesh wise only) an UAZ 452 as a commission
OK, but there were many more performance/sports/racing cars built using compact car mechanics, like the TVR Grantura/Vixen/1600M, Alfa Romeo Giulia TZ2, Lotus 7, DeTomaso Vallelunga, Baja Bugs, Peugeot 404 record-breaking vehicle and on and on... The "Old Yeller" seems to be more-or-less isolated. Definitely in comparison with the ones I mentioned.
i suggest start learning it right now starting with the wiki because it will take you a long time to learn it to create a whole vehicle