if the only difference between the two is the size of the cab, my opinion is simple...extended cab.
the wheel base is about the same, correct, so the difference comes into how much space you want in your cab. i have seen numerous people trying to fit their b pillar inside a standard cab, and always complaining of how cramped it can get, especially for larger people. they'll sometimes put the b pillar outside the cab, but then their harnesses are mounted outside...
some people would say an extended cab allows more room for adjustment, possibility of a 3rd seat, but those aren't necessities for a race truck, unless you want to drive it when you aren't racing.
the question is: what do YOU want to build? the standard cab could be a nice little race truck with nothing left over in the end, and an extended cab can make it easier to move around in.
I agree totally. I 100% prefer the extended cab short bed but not sure if there is a downside to the wheelbase being longer than standard cab short bed. I have heard of extended cab f100's being built with a shortened wheelbase, the same as a standard cab.
i agree 100%. with the extra room in the cab you can fit that third person and have some room to store tools, on board air compressor and other things you might need when you prerun. but either way you go build it the way you see fit.