Before you figure out what size socket to put on your impact, it’s important to get the truck sitting where you want it; imagine the car driving down the road and that’s what we call “ride height”. You don’t need to know what engine you’re using. You don’t need to ‘predict’ how much the car will drop or rise as soon as you add fluids, swap in aluminum heads, or change any other variables during the build. If you have the ride height established, you have enough information to begin measuring for a Welder Series Mustang II crossmember installation. You can adjust the spring rate at the end of the build to support the car at the designed ride height.
It’s a great idea to have the wheels and tires you’re going to use so that you can place them in the wheel opening and mark your spindle centerline. Even though the wheel base was determined by the manufacturer, sometimes when a vehicle is lowered substantially, the factory wheelbase just doesn’t look “right”. It could be that moving the tire forward or backward 1/4″ centers the wheel perfectly… someone checking out your car at a cruise night has no idea if your wheelbase is accurate to factory specs, but they’ll sure be able to tell if something looks off between your wheel and fender.
I jotted down (I was going to say “wrote”, but I’ve seen “writing” and mine looks nothing like that) a bunch of dimensions before going at all the fender bolts. I also knew I wanted to tuck the bumper in a bit, so I made that measurement while everything was still together.
When I find some room to keep all these parts I’m removing, I’ll start into measuring for the Mustang II crossmember kit.