Best Pontiac Powered Stockers

[oldskool]

Originally Posted by Mike Jones

From georgeklass.net

Yeah, there are several of those classes from the early '60's that I still don't understand the rules for.

So, exactly what was the difference between classes like S/S, OS/S, & A or B/FX. Can anybody here explain the rules for all those classes ?

Here's the best explanation I've read, so far.

"...The factory drag wars were just heating up in 1961, and for the Nationals, the NHRA introduced the Optional Super/Stock (OS/S) class for cars using special factory components that were not yet factory equipment...In 1962, OS/S became the Factory Experimental (FX) category..."

For Pontiac, I suppose those "special factory components" would have been 421SD parts, which were not an option on the body being raced.