Model A frame front suspension.

[Matt167]

Looking at the money site ( Speedway ) on my front end options.. I’m 50/50 on boxing the frame or not. It’s going to be low Hp as I just want to use a Mercruiser 4cyl and a manual transmission. I know they say cross steer is a No no without a boxed frame, but people have done it.

The front end kit I picked out was spec for A-32, radius rods and a 47” I beam. But the Superbell axle is back ordered. Then I got looking into Mustang steering boxes for traditional steering BUT I don’t want a 4 bar. Can a Mustang box work with a radius rods? I get that the suspension has to travel in the same plane to prevent bump steer

Or should I go cheap, get the $560 48” tube axle spring over setup and run the Vega with boxing plates? My cab is 48” wide so it’ll look right either way

 

[earthman]

It seems we assumed someone else is going to reply to your question Matt. Sorry for this late response. All i know is my model a frame is not boxed with a Ford 2.3 4 cylinder. It has traditional steering with radius rods. The box is mounted on top of the frame so the drag link is nearly level. The frame is internally braced under the steering box. Still has the model a rear axle so you know i don't drive it hard. Works fine.

 

[Matt167]

It seems we assumed someone else is going to reply to your question Matt. Sorry for this late response. All i know is my model a frame is not boxed with a Ford 2.3 4 cylinder. It has traditional steering with radius rods. The box is mounted on top of the frame so the drag link is nearly level. The frame is internally braced under the steering box. Still has the model a rear axle so you know i don't drive it hard. Works fine.

Do you still have the enclosed driveline? I’m going to run open driveline The Mercruiser is comparable to the 2.3L. As far as HP is concerned

Corvair box?

 

[earthman]

Open drive with the speedway adaptor. Used what was supposed to be a f100 box from ebay. It was similar but from a larger truck. Corvair works too.

 

[smallfoot]

I didn't go the same route on mine so I didn't comment. My 31 is set up with a Model AA front section of frame spliced onto a Jeep CJ/Dj frame. Front axle was from f100 and I control steering thru a 73 Gremlin Saginaw steering box mounted on the inside of the frame with a huge bracket which stiffens my frame at the steering box area and the jeep frame is partially boxed midway of frame. Running 350/350 and no problems .

 

[Bamamav]

As light as it will be, I’d want a Vega cross steering setup. That way the box is up front out of the way of the exhaust. All you would need would be a pan hard bar running from one side of the frame to the axle. It wouldn’t matter if you had stock or split bones, hairpins or a 4 link, the pan hard will keep it from shifting side to side with the cross steer.

As to boxing the frame, you could just do to the front back to firewall. That’s all they boxed from the factory on my big heavy Lincoln with cross steering. Nothing wrong with a tube axle, either. Henry ran them on the V8 60 cars without any problems.

 

[kenny c]

From my understanding you can't run a tube axle with split bones. there isn't enough twist in the tube like in an I-beam. the bones tend to break. Hair pins and 4 link seam to work because they flex. I used a Unisteer rack on mine but but neither build have made it to the road yet.

 

[Matt167]

I was curious about the unisteer racks. I’ll be running radius rods..

Is the factory caster angle enough on the front crossmember? I was told by someone I pretty much needed to install a 32 crossmember, but there all actually modified A crossmembers in the aftermarket. They all list 7* caster tho.

I’m using my stick welder for the structural welding. It’s a DC unit so I can run it lift tig if I want to. I’m not setup for that yet tho

 

[Bamamav]

You can set caster with a wedge spring mount. Of course the bones will have to be set farther down at the frame as well.

 

[kenny c]

The Unisteer rack is supposed to take the place of a Vega setup. I started from scratch with a stock 32 heavy front axle and I built my own frame. I set the cross member at 7 degrees and cut and reweleded the split wishbones. This was to keep the rear mounting point high enough to mount them in the frame and parallel to the ground.

 

[Old Iron]

I installed a Dodge Omni manual rack on my 37 GMC and absolutely love it.
It's in my 37 GMC build

 

[bob w]

I've used VW Sirocco and Chevy Geo rear steer racks on beam and tube axles. Worked well, but if there is a next time I'll use an Omni rack thanks to Old Iron.

 

[Matt167]

Would that pretty much attach to the crossmember after making a mount for it? I’m going to front mount the engine using a hurst mount. Will make things a little busier up there