Welcome to the site, although I`m also new here, after reading your post on your Merc, it reminded me of an article some 20 years back in street rodder mag, it was also on a `49 merc, they used a complete `67 pontiac lemans frame and lowered the merc body down over it, and bolt for bolt it lined up with the lemans frame mounts, the only mods they did was trim the front frame horns back about two inches...the wheel track was right on the money. just some info for those that are interested.