i got a 54 chevy and i am planning on installing a fatman ultra low crossmember in the next couple of days someone told me 16'' from the front bumber bolt holes?? how do i properly locate front axle centerline??
Measure from a spot on the body, maybe the front edge of the rocker panel forward to the center of the spindle before you take the old front end apart. Write the measurement on the rocker for future reference. Make sure the wheels are pointed straight ahead, measure both sides. Now you have a centerline measurement for the new installation.
forgot to mention i took the body off the frame i havent started to remove any suspension components yet i dont wanna eyeball this one...
What he said. And run a plumb off the end of the stock spindle's both side's, mark the floor. Mark the top of the frame rail as well w/ the stock spindle centerline as your guide. Of course, the vehicle need's to stay put and level.
In that case, it's best to use a plumb line from the spindle centerline on each side, and mark the floor. It would also be best to do this with your old suspension at stock ride height, providing your bushings are in decent shape. It's a good idea to make a couple more plumb lines for the centerline of your frame front and rear too. Just in case your frame moves while up on jack stands when you're sawing and hammering away, you'll know where it was when you started. After you get the front end out, and the frame cleaned up, install the crossmember with the A-arms and spindles, again at ride height. Find center for right and left, tack weld the crossmember in, and check again for axle centerline and any other important measurements like caster, etc. This is putting it in simplistic terms, but you get the idea. Rod & Custom and Streetrodder have both done at least half a dozen articles on this, some of which were on the '49-'54 Chevys. Do a search on their websites for the tech articles. Good luck!
I did this on my 53 (same crossmember but added dropped spindles to get it even lower). one way is to place a straight edge from Ball joint (or spindle) to ball joint on the upper arms.and draw the line. another is to find the center of the fenderwheel (top peak of the opening (not at the bottom) and move forward a 1/2 to 1"" so visually if will look right (this is not the preferred way unless you do not have the front susp in anymore.. The instructions are usually good on Fatman stuff (I have done two so far). but with no body that is tough to do (unless you mock it back up) one more way is to draw a mark on the floor where the center of the tire touches and draw a line between the two. take a straight edge across the frame rails with a plumb line/ drop line (when it lines up with the floor you are in the right location (more forward of line slightly to be safe) nothing worse then having the front tires to far back in the fenderwell opening..
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