1. Place a long piece of angle iron 2 3/8 inches behind the centerline
of the hole in the forward body-mounting bracket. Make sure the iron is
at the same position on both sides of the frame. This will provide a
good reference point and will retain the stock width between the framerails
after you remove the front-end. Place a good tack-weld on both framerails
to ensure that everything stays put when you do the cutting.
2. Locate the centerline of the truck's straight-axle by measuring 28 3/8 inches forward of the reference brace. On '53-'56 Ford F-100 models the axle center is 27 inches forward of the center of the body mounting holes.
3. Secure the frame in the jig and check for the proper ride height.
For a good slammed stance, set the lower edge of the framerail at the
centerline of the stock axle at 11 inches off the ground or, in this
case, at the bottom of the frame jig. Next measure the ride height
farther back on the rails at the horizontal area just before the frame
starts its rise over the rear axle. There should be 12 to 12 ½ inches
between the underside of the frame and the ground. The measurement at
the back of the frame should be 16 to 16 ½ inches from the underside of
the frame to the ground.
4. In the front of the car, the underside of the front crossmember/core support should be about 9 inches from the ground. Jackstands can be used. Briggs worked on a bare frame taking measurements to the bottom of the frame jig.
5. Hold the tape measure on the cross-brace /reference point and
measure forward to the middle rivet that holds the crossmember to the
framerail. Record this measurement to use as a reference when you reattach
the front portion of the frame later. Measurements of this area and the
lower center of the crossmemeber are very critical and must be accurate.
6. Measure 14 inches back from the predetermined centerline of the axle. Use a square to mark the rails across, down and on the underside. This is where the first cut will be made on the truck rails.
7. Briggs used a plasma cutter here. But cutting torch or a sawzall
will work. Try to hold as close to the line as possible to keep the
cleanup grinding to a minimum.
8. You marked off the section of the frame to be removed for the swap in Step 6. You can cut it at this time.
9. Cut both framerails and set the front section aside (this
front portion will be needed later). Grind the cuts smooth and clean the
area near the cuts to leave a good surface for welding.
10. Checking the two frame sections at the mating area indicates that the Camaro frame measures 37 inches across from the outside of the rails. The early F-100 frame measure 34 inches across from the outside of the rails and must be figured in when you set up the two later.