The Stovebolt Site Forums The Shop Area The HiPo Shop 37 chevy 2 questions

rear fender inner bracing, any pic.s ,measurements what do they look like? both of mine are cobbled together and not the same. HELP , going to put a hot 350 or 383 in truck to drive .besides boxing for componets / upgrades how far should I go boxing out or adding additional bracing? thank you for all help.

You will want some flex in the frame, so boxing the whole length would not be good. I added some plate to my '37 where the motor mounts were welded in and at the back where the extra shock absorber crossmember was added. I probably went 6" for and aft of the mounts with same thickness flat plate.

As for the rear fender braces, mine were long gone by the time I got the truck. I have fiberglass rear fenders, so all I did was weld some 1/4" round stock to a flat plate and mounted it to the frame rail just past the tire. I used what I thought was stock mounting holes. Out at the fender I had a second plate welded to the round stock. I bent them down to meet the fender where I thought they would do the most good. I had to glue the plates to the fenders so no holes would be needed to be drilled.

When boxing a frame for some good reason, it is best to taper the end of the box viva a "V" shape, either pointing forward or backward the ease load transion from the boxed to unboxed frame, otherwise the abrupt termination of a squared load can lead to frame breakage.

Ed

What Ed said. Any sharp transition forms what's called a stress riser. The boxing plate should be formed into a "U" shape with the ends where it's welded to the frame tapering to a point.

I just fixed up some boat seat frames that had a right angle transition from the vertical to the mounting plate. They had cracked right at the sharp corner. The previous owner welded the crack, and they promptly cracked again. I welded in a fillet so the transition to the baseplate is now about 120 degrees instead of 90. We'll see how it holds up, but I expect not to have problems in the future.

thank you guys for help/info. definitely helps dredging old skills and memoirs up not used in a very long time!

Definitely don't overdo it on boxing. When I was building dirt track cars from tri-5 Chevy frames, we did a lot of boxing- - - -and a lot of crack repair. We needed a stiff enough frame to hold jackscrew suspension adjustments, but even building the roll cage like a bridge didn't eliminate frame flex. You're not going to, nor do you need to make the frame totally rigid.
Jerry

"You will want some flex in the frame, so boxing the whole length would not be good. I added some plate to my '37 where the motor mounts were welded in and at the back where the extra shock absorber crossmember was added."

Joe H,

This is a subject I have been interested since I was a teenager reading about your dad drag racing Pontiacs. Over the decades Iv'e read numerous articles about "Boxing The Rails" to add rigidity by converting a channel section frame to rectangular tubing. If that conversion is made on the frame from end to end it seems that there would be no abrupt changes in strength along the frame to concentrate stress and cause failure. Can you please explain why that is not so.

I have '32 Ford roadster street rod that has a fully boxed frame from one of the big street rod component suppliers. Although it's just a weekend toy it does have over 22,000 miles on it and the frame is fine. On of my neighbors had a very similar roadster with the frame boxed only in the engine/trans area and it developed a nasty crack near one of the engine mounts that required some really unsightly repair work.

Looking at the Speedway Motors catalog it looks like their street rod frames are rectangular tubing.

"This is an apple- - - - -this is an orange- - - -now let's compare them!"

Here's another well illustrated Hot Rod Magazine article on boxing the rails.

http://www.hotrod.com/articles/0708...-01-pl-boxing-the-frame-boxing-the-frame

Nothing has change since I was a HRM subscriber in the 1960s and my son was a subscriber in the 1990s. It's still a lot of work but must be worth it or people wouldn't still be doing it.

Here's the same issue addressed on this forum a while back:

https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=332001&page=all

what thickness would you gentlemen recommend, to box out? 37 innerbracing rear fenders pic.s measurements?