Broken frame gusset on a 67

[Tom K.]

I put my 67 BB vert on the lift the other day to start spraying bolts in preparation to remove the body soon. While I was looking I noticed that the differential crossmember was not level. Upon further examination I found that the left gusset plate is broken. Is this common on these cars? I'm sure that this car was drag raced in it's younger days. The car presently has a 350 in it and has not been driven since 1982. It appears to be broken rather than rusted away. There appears to be only surface rust on the frame.

[Thomas N.]

Re: Broken frame gusset on a 67

The sombreros on the frame (that the rubber inserts of the rear crossmember taper lock into) have very little surface area that is welded to the frame. As a result under aggressive loading, these welds break loose, and provide the situation you have. And it usually is the left side (I think it is the way the torque reaction is). Also, when the sombrero lets loose, it has the tendency to put a hole into the rear deck fiberglass, underneath the carpet. Once you drop the rear crossmember, you can weld a new one in. I recommend you get a new one, so when you grind the old welds away, the ears on the new piece will locate as they should. It can be done with body on, but with body off, it is a cinch.

[John H.]

Re: Broken frame gusset on a 67

Tom -

That's a fairly common issue, especially on big-blocks; photos below show both variations of broken sombrero bracket welds, both on the same car - a California '67 400hp 4-speed.

[Tom K.]

Re: Broken frame gusset on a 67

Thomas & John, Thanks for the great information and the pictures. I suspected that it was common, but I couldn't find anything in the archives. I know that this was a 390 or 400 hp in it's 1st life. I have a picture of the car dated 1975 and it has a small block hood on it then, so I suspect that the BB & orig 4 speed left b/4 then. My plan is to make a safe & fun driver out of it with the hopes of someday maybe acquiring a 427 for the car. I've learned a lot on the TDB since I joined NCRS and the St. Louis Chapter. I'm sure that I will have a lot more questions as I progress.