Thread: channeling

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Hey to eveyone, my name is Chris. I'm looking for anyone with some insight on channeling Model A bodies. I own a 28 sport coupe that I'm building and I want to channel the body 4 inches as to hide the frame rails. I need photos of inside, underneath or in progress channel jobs so that I can be sure that I do this structurally correct. If there any sort of body diagrams or tech articles for the model A that might have this info, that would be a great help, too. Thanks.

Howdy, all,

This is something I have been wondering about, too. Having never built a roadster type rod, I've never looked at one close enough to notice just how the floor and supporting structures were built. And, since I hope to be able to put a bucket or something similar together in the future, this seems as good a place as any to ask. Just how do you channel a body, and maintain structural integrity??

Since my "buddies dumped on me" I'll give you my best shot. Sorry, no pics, but in time someone else may show up with some.

You didn't give a clue as to what your condition is so I'll shoot out something generic with some caveats. If you have enough skill to do the job you should be able to figure it out from there. And, as with any of these kind of modifications two different folks will have at least two different ways of accomplishing the same thing. The rat rod crowd might think my way is too complicated, but if you still have the car later on when the RR fad dies you may want to finish it in a quality way, so a little more work now means a lot less later.

First thing I would suggest, especially with the sport coupe, cabriolet, or roadster, is to make sure you fix the inner structure of the body above the floor pan before removing the body or cutting out the floor. Make sure the doors and deck hang right, the openings are square, and any rotted wood is replaced, preferably with steel. Squaring the openings is usually done by shimming (controling the "twist" ) the body on the frame. Once that's done weld in some cross bracing inside the passenger compartment, vertically and horizontaly, to maintain some rigidity when you cut out the floor. Don't take the vertical bracing down too far to where it will interfere with welding in the new floor later, stay just above that point. Then you can deal with cutting out the floor one of two ways depending on space and equipment available. You can remove the body from the frame to cut the floor, or leave it on if you have a way to suspend or block up, and cut the floor then. Either way, before repositioning the body, block the frame level. Use tools not your eye to determine level. Also, make sure the frame is square before proceeding, and if you intend to box it, get that done too.

Cut the floor around it's outer edges, leaving a small amount (say 1/2") as a flange if there's enough material left originally. Lower the body over the rails the amount you want to channel it. If you've got a block and tackle (come-a-long, whatever), and a strong enough beam overhead that would be easiest, but it can be done with some buddies on the corners. Either way, block the body solidly so that it doesn't move. You will again want to have the doors and deck lid off and make sure that you square up the body openings in it's new location. Square up the body around the perimeter of the frame (this is why the frame needs to be square to start with). Make sure the body doesn't tip, rock, or slide easily on the blocking as you'll be climbing in and out, over, under, around and through several times. Stand back and look at it to make sure you're happy with the look. Some like a straight drop, some like to work in a little rake (usually down in front). By now you might have figured out you forgot to notch the firewall. That would be part of the baptism process! Not only does it need to be notched for the rail, but also additional clearance for the transmission bellhousing (you do have a mock up engine/trans in place don't you?)

Once you're happy with the placement of the body weld in some temporary scrap pieces of small tubing or bar stock at four points on the perimeter of the body, tied back to the frame. These will help keep the body where you want it so that when Bubba comes over to see what you're doing, and leans against the body, it won't move off your blocking. And while you're mocking stuff up, this would be a good time to see if you'll fit in the car when you're done. If it's a topless car, headroom won't be much of an issue unless you plan driving with the top up. If it's a coupe, stock heigth won't be too much of an issue with a 4" channel (depending on how tall you are), but if you've chopped it, then make sure you still fit. One of the bad things about channeling is that your foot heigth in relation to the bottom of your butt gets flatter. This is very uncomfortable for extended periods of time (also affected by your age). Try to use your eventual seat arrangement, tape in or allow for a headliner, and put in a temporary piece of floor at the eventual heighth. Even better would be to mock in the steering column and wheel you intend to use. MAKE SURE you are happy with your seating arrangement for comfort. If you really only intend to do short drives, you can probably tolerate almost anything, but for longer drives a bad sitting position can take all the fun out of a car.

Now comes the part you thought you could get to much earlier. What to use for a floor? There are almost as many opinions as people. If the stock floor is in good shape, and you didn't butcher it in the cut out process, that's a good start. You'll probably want to fill the parts at the front that were wood with steel, but that's pretty straight forward stuff. Otherwise, some 16 ga. sheet stock will do fine, especially if you take the cut pieces to a sheet metal shop to have some ribs rolled in for rigidity. Some folks would go heavier on the sheet and not reinforce it, but I think it looks better with the ribbing, and won't oil can. A lot of how you set up your suspension will determine how you make the floor. You need to leave enough room for suspension travel, especially if you go to a coilover/four bar set up. The stock Ford suspension will take less room, depending on what you do with spring heigth. If you're not getting too far out on the suspension (or fuel tank relocation, battery location, exhaust size and routing) then making a similar configuration to stock should work fine. Forming the trans tunnel might be the most challenging, again depending on what you choose to use for running gear. Here also, you can make a pattern and have a sheet metal shop do the rolling for you to get the arch you need. If you start out with a piece slightly oversize you can trim to fit. If you're real good at patterning, they can roll and break a perfect fitting piece. And about patterning. Go to an art supply place and get a few sheets of "poster board", it's great stuff for making patterns. And you'll use quite a bit of it when you start to finish off the floor.

If you're having to build your own floor, I like to start with some 1/2 x 1" box tubing or channel, don't use bar stock, it flexes too much. Use these for cross bracing stringers under the floor pan but on top of the frame. Start with one across the B pillars (door post with the latch), another across the back of the passenger compartment (about even with the plane of the back glass on a coupe) and then another at the back of the trunk area, and one just ahead of the rear end. That will give the floor some good support. If you can locate over some stock mounting holes in the frame that would be good, other wise you may have to drill new ones. Take these stringers from existing inner structure to another, or add some 1" box tubing between the existing structure, and weld to those. Now you can lay the new flooring on top of that. If you punch holes (5/16") in the floor sheet over the stringers, you want to plug weld it to them, that way you don't get rattles. If you have access to a spot welder, that would be even easier.

This is where the flange you left around the inside of the body comes in. You can lay the main part of the floor down and then make patterns around the edges to put in "drop down" pieces to seal off the area around the floor edge to the body. When working around the door openings, you want to recess the sides of the floor "drop" to clear door trim panels and any carpeting you might ever plan to run.

I'm sure I've forgotten something, but others will chime in to fill the gaps. To read about it probably sounds worse than it is. It's one of those things where it will become clear to you what needs to be done once you get into it and see how it shapes up. You'll do lots of cutting, cussing, and welding, but take your time, do it right, and you might just enjoy it.

Thanks, Bob, that was very informative. I sort of had that idea, but not having been exposed to the details, I was not too sure.

thanks for all the info, it's a big help.

I don't think a Model A "Highboy" looks all that bad with the stock frame rails exposed. I know that Model As are "tight" in stock form. When you channel the only way to recover the lost leg room is to push the seat back. In a coupe there is only so much give. So, before you get out the cutting tools chase down a channeled coupe or roadster (at a show) and ask the owner if you can sit in it. Driving with your knees in your face is no fun.

You can usually take 3 or 4 inches out of the top before headroom becomes an issue. Consider a chop first.

In the day, channeling was popular on the East coast but seldom seen out West. It seems to be trendy all over with the rat rod crowd. But I would submit that it is a fad. If you are going to drive your rod any distance at all you need to give a fair amount of consideration to comfort.