Just move the passenger's side mount bracket back to the same position as the driver's side. V8's and 250 6 cylinders use the same bracket, they're just offset on the frame rails for the 292. There's no need to use some fancy aftermarket mounting bracket unless the butcher job on the frame has made the stock mounts a moot point.
Jerry
the 292 perch does not just slide back and work. the 292 perch also doesn't come out as far either. you will have a mickey mouse job
ron