I have a 1947 Ford that is going to have a 502, th400 and running on 44's. I want to keep the stock frame rails and was wondering what the proper way of boxing the frame would be. It needs to be strong and look good.


Thanks Eric

Also can you mount a Ford 205 behind a TH400?

the best way I think to box a frame rail is to take cardboard and make templates to just fit into the channel for a couple of feet at a time. then trace them onto the sheet steel and plasma cut it out or if you have a vertical bandsaw this would be easier to follow the lines in the curves. when you go to weld them in only put about a 1/32 -1/16 of the thickness of the plate into the channel so that you can get a nice outside corner weld. start by tacking it in about every 6-8" apart then go to the next piece. once you have all the pieces in and are happy with the fit (BTW leave like a 1/8-3/16" between the ends of plates) start welding it in only about 2-3" at a time then skipping around as much as you can.when it is all welded in take your 9" air sander or angle grinder (at least finnish with the air sander if possible, it looks alot better) and try and turn it into a square edge, you may have to do some more welding on the low spots. once you have all the low spots filled in and a nice 90deg. corner, take your air grinder and keeping it as flat as possible put a slight radius on the corner. I have done alot of boxing and even went to tech for chassis building and this makes for great results. just to warn you it takes a while to do all the grinding and filling of low spots.
John

Buy some 1/8" plate and scribe it to fit inside the frame rail, weld it in place using short welds not letting any area get real hot. I'd hold it about 3/8 - 1/2" inside of the edge, so the welds won't show.
If you weld the plate to the edge you will need to do a nice looking weld, or end up grinding and filling at the corners.

thanks