NASCAR EXHAUST DUMPS

[pulln4dejr]

Okay guys not sure if this has been asked before but I’m wondering if some of you Vintage NASCAR guys can answer these questions :

1: When did NASCAR go from single dumps out of each side to dual dumps seen on Monograms GM’s?

2: What size Plastruc Tubing is the right size for early models?

Just trying to make them as accurate as possible for future projects!

As always “thanks for responding!”