You car must comply with its homologation form, basically or partially or totally. Appendix K is above everything, including mistakes of course, you must stick to the safety requirements and all the things about Voitures de Tourisme de Série. Appendix J, you must select which year concerns your car and try to find interesting things. No DAF homologated or entered in an itn' race? Drop dead and go Volvo!
Then comes the period correct or period proof thingy. Interesting but risky.
You'll quickly learn why you've better wear a helmet prior to racing! By the way, in your region, how is going the half potato market?
PS The last two are genuine poor jokes, nothing against you, its obvious. Historic racing is a matter of celebration and I can't see why we could celebrate our elders other than making fun with passion…
IMHO and BIMBO! Cheers!