The class designations A, B, C etc. are based on power-to-weight ratios. Here's a link that explains it.
http://www.gassermadness.us/Gas_Classes/index.htm
Decided to go with a dual quad setup in lieu of the Webers. Not aware of 2-4V setup for a SBF in scale so I modified the unit from the Revell 427 Cobra SC.
The photo was from a previous thread showing what I used to build a roll cage. The styrene rod is for scratch building. I do use bits of scrap for my liquid plastic mixture.