Dear Welder Series…
Just curious, how much below the bottom of the frame does your Mustang II crossmember come down?
Mike
Dear Mike…
Mike, the answer to this depends on the distance from the ground to the bottom of your frame at the ride height you want, the tire size you will use, and if you are using stock or dropped spindles.The bottom of our crossmember is 1-5/8″ lower than the center of the lower control arm pivot bolt. The stock spindle height will be about 3-1/2″ higher than the lower arm pivot bolt. A dropped spindle will be about 2″ higher than stock. (The top of our crossmember is about 5/8″ higher than the lower arm pivot bolt center.) The rack sits higher than the top of the crossmember. The engine should not be installed until the rack is in place to be sure the pan clears.
An advantage of our crossmember is that you decide how you want the frame to sit and we tell you how to notch our crossmember and towers to achieve this ride height.
It’s easier to tell you how much ground clearance you will have for a given tire diameter. Suppose your front tires are 27″ diameter. The spindle will be about 13″ from the ground. (1/2 of the diameter minus 1/2″ for tire “squat” with weight on it.) With stock spindles, the bottom of our crossmember will be about 7-7/8″ from the ground. (13″ minus 5-1/8″.) The bottom of the crossmember will be 2″ lower (about 5-7/8″) with dropped spindles.
Thanks for a good question. I hope this answer helps.
Paul Horton
I have a 1937 International pickup with a 5.0 liter and I am in the process of installing a stock Mustang II cross member, but I am having a hard time trying to figure out how to get the proper ride height. Can you give me any advise.
Thanks Dave
Dave, we would mock up the truck with the wheels and tires in place. The “proper” ride height is the height you want. If the question has to do with how much the springs will settle when the weight of the engine, rad and all the other parts are added, the correct ride height, ready to go for a drive, is with the lower control arm pivot bolt 3-1/2″ lower than the stock (non-dropped) spindle height. Spindle height is determined by tire size. We use the tire radius minus 1/2″ as the spindle height for a give tire size. A good site for tire diameters is http://www.miata.net/garage/tirecalc.html .
Use a floor jack and some blocks to hold the frame at the height you like, front and rear. If the spindle height is more than 3/8″ higher than the bottom of the frame rail, the frame will have to be notched for rack clearance. If the spindle height is lots more than 3/8″ higher than the bottom of the frame, it might be better to use dropped spindles.
Thanks for asking.
Paul Horton