It is the single belt with idler. Vintage Airs website just says it is a Stewart Hi-Perf Aluminum Water Pump. It would be Tuesday before I could call them but it is the pump that came with the kit. I cannot find anything on their website that refers to a reverse flow water pump. The replacement part number for the big block is Part #: 72231-BCP on vintage airs website. That is for the short pump. Not sure if his cars got a short or long pump.Is the Vintage Front Runner Kit a single belt? If it is would that not require a "reverse" turn water pump? I would make sure you have the right type pump before changing radiators and such.