Do you have a CMC with the front bulkhead depression for the gas tank? If you look under the dash, there is this tremendously big bump down in the bulkhead, which the gas tank sits in, basically. That only provides for a little foot clearance (only a few inches) for the pedals. Not cool, but most of us have to live with it (or go to a different gas tank and rework the bump, which I've never seen done). It's OK for people with smaller to "normal" feet, but for larger people/feet there is certainly an interference problem.
Secondly, there is the operation of the pedals to consider: Opening another hole in the central tunnel AND somehow welding nuts or something on the inside of the tunnel to bolt the pedal cluster to, figuring out the proper length for a (custom only to your car) clutch cable and lengthening the brake pushrod (probably the easiest part of anything so far) to actuate the brake Master Cylinder. Lots there to consider....
I know CMC/fiberfab/street beast's have this problem with the bulkhead interference, I think Vintage does, too, and I'm not sure about Beck or IM (depends on their gas tank placement). INterestingly, the original (steel) speedsters don't have this problem.
We all just live with it, because it could be a MAJOR PITA and, for a lot of us, moving the pedals back (and the seat along with them to give adequate legroom) gives you too little seat travel, as there's just so much cockpit space front-to-back to begin with.
If, on the other hand, you just want to find out how far from the forward Bulkhead VW placed their pedals, then the centerline of the pedal pivot point is 4 inches from the bulkhead, measured to the bare metal.
gn