In regard to the 348, 355 and 360 Challenge cars they all raced with standard fuel tanks, yes ? In the various historic challenge series, is there any requirement to replace such with bag tanks or are the standard tanks compliant ?
360's had fuel cells that are readily available still. Earlier challenge cars had standard fuel tanks.
It will depend on the regulations, of that specific series. But from scrutineering perspective all the cars I check run FTL 3 tanks, because they run multiple series in Europe and so want to cover all regulations. If they just ran locally, they could use OEM tanks only if that was what the car ran in period in a CUP or Challange series. Jason