How can I adjust wheelbase?

Historically, owners/members here have OEM rear springs, etc... They find oversized tire runs closer to rubs at one side of rear. Then others try to explain why, the engineering involved.
Even though that built in difference wasn't a full 1.5 inches, I'll assume your aftermarket super stock springs change it for drag racing and straight line launch. So what I'm saying is all that 1.5 inches isn't a fault in the right front suspension. You may need to alter both left and right sides to get it equal. I don't know how drag racers set up their wheelbase. Good luck with it.