In this case the original post is about a '48, so thee are some differences to what you describe, but if anything the Bonus Builts are even more dependent on the middle crossmember. That's why I am reluctant to cut the middle c'member for a T-5.

 

Ross, I just moved the middle crossmember back to allow transmission clearance (in my case for an AOD) and added another crossmember specifically for the transmission mount. The original crossmember is now under the area of the u joint. You can either re rivet it or bolt it after drilling new frame holes. If you want to see how important the middle cross member is, step on the running board with and then without the crossmember in place.

 

Question: Is there a supplier for frame boxing plates or is this something that everyone gets made for their trucks? I guess what I need to know is how is the best/easiest way to get this done. I have a MIG to weld them in with but I would need to make them or have them made. I'm sure having them made could get costly.

 

I havn't found much as far as already made up pieces, I plan on making my own.

 

Most folks make their own. If you know someone in a metal shop, you may get a decent price, since they aren't very hard to make.

A good method is to make cardboard templates for each plate. 1/8" material is plenty thick enough. I would buy remnant, or "drop-offs" from a metal supplier or sheet metal shop. They usually have plenty of that kind of stock that is left over from making up orders and it is just scrap to them.

I would cut the pieces using a cutoff wheel in a right angle grinder (since that is basically the only method available to me), but a good band saw, if available, would be much preferred. Of course, a plasma cutter would be the super best way to cut these.

One good suggestion is to use a hole saw (or plasma) to cut large holes (or ovals) thru the middle of each plate for access after the plate is in place for brake lines and wire harness. A solid plate doesn't stiffen the frame more than ones with holes or ovals.

Spray a weld-through primer on the inside of the channel before welding the plates to protect against rust.

Some folks mount the plates flush with the frame legs (which I think looks best) or inset as much as 1/2" into the channel for easier welding. Go slow and move around the frame tacking them in. Don't build up a lot of heat in one place, as this will warp the frame a lot!!! Weld them in using 1/2-1" welds every inch or so. Stitching each plate is fine. Continuous welds are overkill.

One thing to consider is bolt mounting points on the frame. Some attachments will be blanked off by the boxing plates. Either locate the holes/ovals so that access is retained, or weld nuts to the inside of the frame channel at the attachments. I like to use flange nuts for this. You can also weld a crush tube into the frame channel at the attachment and use a longer bolt that goes thru the whole frame rail. The rear-most bed attach bolts are one example that comes to mind.

Good luck.

 

Check out progressiveautomotive web site. They have boxing plates that are cut to fit specific frames.
Scott

 

Randy Jack what is the best way when you get to a crossmember point? I've had some tell me to shorten the crossmember and attach to the boxed section and others say stop before that point and start again after it.

 

I have seen it done both ways. Starting/stopping is a WHOLE LOT EASIER. As to the relative strength of either method, it would depend on the execution.

Shortening a crossmember and reattaching it to the boxing plate is a LOT of work and much more difficult to setup, as the frame has no strength while the crossmember is removed, so a frame jig would be essential. Once attached, only the weld joint of crossmember-to-plate joint is working structurally and stress tends to focus there. This method can look very clean, though.

Starting and stopping makes a lot more sense to me and could be structurally stronger as long as the box plates are also welded to the crossmember. This means the crossmember is anchored to both the frame rail and the box plate, which adds strength to the joint and resists tortional loads better.

Ultimately, either method is going to add huge stiffness to the stock frame.

My two cents....

AXracer should really chime in here somewhere...I'm sure he'll have something to add.

 

Thanks for the input! I've had several people tell me since mine is already boxed to the firewall to leave it alone too since the 351W i'm putting back in won't be that powerful, With the work i have in the engine i might get 325 hp out of it if i'm lucky and thats good enough for a cruiser.

 

IIRC, boxing a frame with a stock suspension will make for a rough ride.

 

It's already a rough ride...how about "boxing a frame with a stock suspension will make a rougher ride"?

 

semantics, lol, semantics.