Thread: Model A frame mod's and axle?

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Does anyone have step by step pics and instructions to Z a stock Model A frame? I plan on dropping it 4 inches and boxing the stock frame.
Also plan on using 4" drop I-beam axle and Ford 9" rear, what are the best widths to use?

I don't know what are the "best" widths, but it will look best if the front axle and rear end are close to the same width. In my coupe I used a Ford 8" rear from a Maverick and the front axle from a '60 Jeep station wagon. They are the same width. My son used a Maverick rear and an Econoline front axle in his A sedan because they are the same width and have the same bolt pattern for the wheels.

As far as your frame is concerned... I partially boxed a Model-A frame once. The next time I undertook a similar project, I found it was quicker and easier to just fabricate an entire new frame from 2" x 3" tubing...

Might be best to just start mocking things up. I don't have any step by step instuctions, but will offer a bit of advice for you.

1. Before you make any cuts, make sure the frame is supported very well, some type of fixturing to prevent the rails from moving around when you cut them.

2. Mock up your suspension and rails at the ride height you want them at, make sure this is the look you want.

3. Measure twice, cut once. Once you have your frame secured to some type of fixture, make sure your cuts are where you want them, and are the same dimension on either rail.

4. Just tack the Z and the rails in place, measure everything from front to back, side to side, and corner to corner a few more times to make sure everything is square.

5. Mock eveything up again, suspension, body, motor & trans, and steering. Make sure it looks the way you want it to and everything fits.

6. Don't weld the whole joint at once. ie weld the top side of the right rail, then the bottom side of the left rail, skip around on your welds to keep from twisting the frame with the heat from welding. Again I would stress how important it is to have everything secured to a fixture when doing this.

This is by no means a complete instruction, just some hints to make the job go better, and the frame to be square when you are done.

I can't help much but my Brookville frame came with a 2 1/2" kickup at the rear based on rectangular tubing. After I had an original A frame sandblasted it came back looking like lace so it may be a good idea to check some rust spots with an ice pick or wire brush before going ahead. The only potentially useful comment I can make in agreement with the above is that the 1974 Maverick 8" rear I have does seem to fit exactly under the A fenders but you have to use 3 3/4" offset on the wheels so you can get the rear right but the wheels have to be right also. The total width of the '29 fenders is 66", stock. It will probably be expensive to have the 9" axles shortened, but apparently there is a better selection of gear ratios available for the 9". The Speedway catalog only lists 3.00, 3.55, 3.80 and 4.11 while there are many ratios available from 3.50 to 6.50 for the 9" if the object is to go racing. I found one site that does offer a 3.25:1 8" pumpkin for a mere $750 or about $1250 for a 3.25:1 with positraction; I guess I will stay with the 2.79:1 that came with my Maverick rear and play games with the transmision gear ratios. It looks like the 2.79:1 ratio is close to the 2.73:1 in the 2004 Corvette and with a 700R4 the low gear of 3.06 and 4th gear of 0.7 the 2.79 rear does not look too bad and may offer acceleration in low gear AND good mileage in 4th gear; then there is a 3.55 gear available.

Don Shillady
Retired Scientist/teen rodder

In his book "How to Build a Traditional Ford Hot Rod" Mike Bishop explains a process for "stepping" the rear crossmember 3". Simple. One cut in the frame and some simple fabrication. This approach minimizes the amount of sheet metal cutting and fabrication in the trunk area.

I don't care for the look of a "Zeed" front end and you can not run fenders.

A 4" dropped axle with reversed spring eyes will bring your front down about 5"

That is the set up I have on my 32. The oil pan sump has about 5" of clearance. The other day I scrapped it going over a speed bump.

I used a forged Chassis Engineering axle. It is 47" king pin center to king pin center. Looks good but you can not run stock 40 Ford style spindles because the steering arms do not clear. I cut the sterring arms off and used stainless steel ones from the Deuce Factory. Chassis Engineering has arms that will clear. If you are going to run fenders the 47" or 46" axles provide a little more tire clearance.

Supper Bell, Magnum, etc offer a 48" axle that will clear the stock steering arms.

If you run a split wishbone you will need to heat and bend the stock steering arms or use dropped arms available from Chassis Engineering, Supper Bell, Magnum, etc.

The object of the exercise is to end up with a rod that has the correct stance. The only way to get this right is to start with your wheels and tires. Do some mocking up before you start cutting or comiting to specific parts.

If you really want low I agree that fabricating a chassis with "Zees" at both ends is the best way to go.

The Maverick 8" rear end is a natural. Most are 2.79 ratio and 3.00 is also common. 3.25 and 3.55 were produced but not offered in Mavericks or Comets. If you want the lower ratios you will have to do some hunting.

Buy Mike's book. It has a wealth of information that can be adapted to most early Ford hot rods.

Hope this helps.