Do I have to box frame, for a stock flatty?

I have a model A frame I want to put a stock 52 flatty in for my roadster. I know it is probally best to box it, but I really like the look without. Will it really flex that much? Can I just box it under the body, where you don't see it? Or just suck it up and box the whole thing...

 

It's 85 horsepower ... you'll be fine un boxed - You might consider an x member out of a 35-40 frame though

 

It's not just the torque of the motor. It's also drivability and stability at higher speeds on modern roads. Stock A frames are flexy. It's a good idea to do it. Like said though more/better crossmembers go a long way.

 

Uh oh... another bluebear/coddington drama filled discussion?

 

It doesn't have to go there.

The car will drive fine and be plenty safe unboxed.

It's also a good idea to box it if you're gonna run wider tires, go faster, paint everything nice.

 

hahhahaha I saw that episode yeas ago! But I couldn't remember what motor he had for it... and if my boss was paying me and paying for my build you better believe I would have boxed it with a big ass smile on my face!!! like this

 

TOTALLY! I think it was a flathead too... But with Coddington paying... and using his shop....? I'd have one nice AV8 ! (damn kids!)

 

Model a frames are kinda flimsy. Box the front at least and put a k member in it

 

as Boyd said, box it

 

Years ago we were questioning the same thing and a good friend and mentor told us to grab a couple of concrete block and set left rear corner on one of the blocks and the right front corner of the frame on the other.

Then both of us stood on the opposite corners,,unbelievable just how much it flexed.

Personally,I wouldn't want to ride at today's speeds with a frame built to to flex on rutted out dirt roads. HRP

 

This is a pretty well debated topic.

For reference, the Bishop/Tardel roadster with a nicely built flatty was unboxed and Vern, with all of his builds and expertise, should know! Yes, there is a '32 k member installed.

 

With a Flathead V8, No.

 

Everyone says that, "You strip it down to a single piece of metal & you could bend it". No Shit Einstien, you unboxed the whole car.

"Box the front at least" How much flexing is going on between the front motor mount & the rear trans mount (Real world, with engine installed/car together)? Wouldn't Boxing the back be better?

 

I boxed my A frame for a 110 hp 4 banger, but "step boxed" the plates back in a little ways so it didn't make the frame look like a pile of 2x4" box tubing. I like that look and it stiffened the frame up tremendously. I also built a K member into the center crossmember and that helped out too. You could torsionally twist the unboxed frame several inches by hand. Once boxed you can jack the whole car up by one corner and it will twist maybe 1/2" or so.

 

Are you going to drive it on a pool table? those Model "A" frames bent from the weight of the stock 4 cyl. bouncing down the road. there just isn't enough vertical depth to the frame to have the strength in bending you would need (not even thinking about twisting, torsion, etc.). 40 years ago I restored a`31 roadster to stock, I had a difficult time finding a frame that wasn't bent at the rear engine mount area. I would see many restored model "A"S with a gap at the bottom of the hood/cowl, because the frames were running up hill, the radiators were higher than the cowl.
boxing the frame in that area would at least double the strength in bending. a `32 frame was made 2" deeper there, to help fix the problem.
Run a straight edge along the top frame rail, stretch a wire or string, it should be flat. see if it isn't already bent.

 

X2. if you're not going to box it, at least triangulate it to keep it from twisting or 'laddering'.

 

I built this model A with a 8BA Flattie, 39 3 speed and a quickchange V8 rear and did not box the frame. After all was said and done, I wish I would have boxed it, they will ride and drive better no question about it. For the small amount of cost and work to do it why wouldnt you?

 

My roadster pick up was not boxed. The frame would flex enough that the doors would fly open when I'd angle into a driveway.

 

Thanks for the info guys. I was hopeing every one would say don't... but looks like majority says box it. Its not the work of doing it, I just like the original look. Looks like I need to pick up some metal this week.

 

If you are worried about the look (which was why I didnt do mine) you can set the box plate in a little and it wont be so obvious.

 

why even chance it? i wouldnt worry so much about the torque from that flathead as the weight its putting on the frame. a 90 year old frame+A heavy engine+one bad pot hole=your done

 

You might spend some time thinking over what you may need to do prior to boxing. What are you going to need to bolt to the frame....shocks, headlights etc. Make provision up front.

 

The only thing I can think of is probally the steering box... I guess I just won't box it at that spot.

 

My buddy has been running a Boss 302/4 speed and 9 inch rear since the 70s in his five window deuce coupe. This car is his daily driver it is out 365 days a year. It's the original 32 frame and is un boxed. This guy is 75 years old now and the one of the smartest mechanics I have ever met. He explained to me years ago that unless ur going racing (AND I MEAN FFFFAAAST! why would anyone ever need to box a chassis?) his words not mine. I explained one time that I was collecting parts to build a flathead powered "A" rpu and was going to box the chassis ,after talking about it he explained to me that it's a waste of time and money for a street car. My 2cents

 

My rpu is boxed up front and K member. Doors do not pop open. Handles like a go kart.

 

I did a stock flatty in an unboxed frame. Got about two thousand miles on it so far with no obvious issues.
Just really like the look of an unboxed frame.

 

I'm with russco....step-box the frame so you still have the "look" and the box! It gives you a little room to run tubing/wiring also! That's what I'm planning to do!

 

Drill lightening holes in the box plates where visible, and it'll look even better than stock. The frame horns don't need to be boxed.

 

Ghost I'm sure your buddy's car is cool and all but there is a huge difference between a 32 frame and a model A frame, again you don't have to box them they will work without it but it will ride drive and handle better if boxed. The cost is minimal and the work is too if you already have it apart.

 

BOX IT! It is such little work and it will stop fatigue in its tracks. Think about and then question all the twisting that 80 year old steel is gonna take - not to mention what it has already seen? When you box, you lock the movement in its place. Not that she won't move anyway after, but for 20 bucks in steel, BOX the rails (at min, the front half of the frame past the bell housing).