Your bench seat may just be stuck on the track/guide. The adjustment cable on mine snapped and the seat was stuck somewhere midway on the track. I ended up using stainless braided line (garage door cable) that you can find at most hardware stores and a U-type Wire clamp, then tied it to the adjustment lever base and the far corner, as per the original design. A turnbuckle also gives you some more adjustment if you can't get the tension right for the adjustment lever.
There are other ways to adjust the pedals. You can upgrade the brake booster to a dual-diaphragm and choose to not use the 1/4in spacer. The brake pedal will sit closer to the driver. You can also use an accelerator cable spacer, which early ford mustang owners used to adjust the pedal height as there was no mechanism to do so. Obviously whatever mods you do, take your own safety into account. It's purely your call.