What will my 68 Dart 408 run in 1/4 mile?

Thanks for the picture Jpar. Unfortunately that won't work for me.
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With my springs being moved into the frame I can't use a spacer but I could weld up my holes and re-drill a new one back a half inch.

I actually ordered my driveshaft a hair longer then stock so I checked and I can definitely move the axle back a half inch or even 3/4 of an inch without adversely effecting the driveshaft yolk.

No reason to mess with with that, redrill the spring pads on the rear