Technical Z"ing a Model A chassis

Newbie chassis question,im looking at Z"ing my Model A chassis.at the rear,is there a set distance from the rear cross member that you make your cut?.once ive worked out the height of the drop does the piece added have to be at a certain angle (15 degress) or can it be straight up and down?.and pics and info will be greatly appriecated.

 

Something like this:


This is fishplated on the inside, wherever there is a seam, and fully boxed.

Where the kickup is done is largely a factor of what suspension you are using, so it does not interfere with suspension operation, or prevent you from installing it.

This was done with sections of another Model A frame, selected to match the taper, to replace the removed section, as to not lengthen the frame.

 

Stepped mine the width of the frame, the only distance requirement I see would be the amount of the Z and room to keep the wheelbase the same. I'm running a flathead and didn't box the frame since I cut the frame at an angle and welded the rear section on top the frame and then closed in the ends.

 

thanks Guys,how many degrees is the piece you added 15-18 degrees?.

 

I built my frame pretty close to model A specs. I would think that where you make the cut would depend on rear suspension you are going to use and how much you are going to Z the frame. I made 6" Z in mine and used about 45 degrees on the kick up. I would also consider where to Z the frame based on where you might want the subrail to be cut.

 

The "easy Z" on a Model A frame is to just cut and lower the rear 6" of the frame down to the lower level of the rail like The Bishop-Tardel book, and Model A Gomez shows above. This will allow you to use the stock subframe in your body with only a small notch removed from the inside edge. And you just leave out the wood block that was stock back there.

 

Here is another one, about 4"

 

45°

 

Why 45*?

 

Balanced loading in compression and tension.

 

Nice

 

I’m in the process of doing the exact Z. Did you make the gussets or did you cut up some rectangular stock?


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You can make your own if you got a press but the easiest is to just cut some tubing.

 

That’s exactly why the spring shackles set at 45* when things are right. Balanced load between weight compression and preload tension.

 

Like Alchemy stated if the kickup is positioned correctly the rear subrail crosspiece only needs to be notched at the kickup. I built this frame out of 2"x3" rectangular 1/8" wall back in '67. Made it to fit the '29 A body, the kickup was 5" and all fit together well. It was also 45 degrees as others have recommended.