Working on a 67 convertible 442. Frame is bad on drivers side. I have a hardtop frame for a temporary replacement to move forward repairing and fitting a few things. Has anyone used a hardtop frame as a temporary solution? Does anyone make the boxed side sections?

 

Dan, the hardtop frame should hold the car through everything but torsional load. I think you should be ok, but you may want to make some stiffening bars for the body while jacking it and rotating it. I would think it would be ok to just hold the body for repairs, though, from a mechanical eng perspective.

No one makes the closed sections. They're more precise than just hot rod boxing it in. I believe Run to Rund on here cut them out and transplanted them, slowly, weld by weld.

67 also had a "heavy duty frame" which was the convertible frame, under hard tops with that option. Very rare.

Good luck in convertible frame search.

 

Koda is correct. The convertible frame IS a hardtop frame with the reinforcing sections welded to it. If the rust on your is confined to the part that's common with the hardtop frame, you can cut out the convertible reinforcements and weld them to the good hardtop frame. This photo is a 68-72 frame, but the 64-67 frames are similar.

 

Thanks for the replies. I’m well aware of the differences I just need to safely put the body on a good frame to test fit parts etc

 

I think the hardtop frame will do that for you.

 

with both frames out, it is the best opportunity to grind through the welds holding the boxing sections, and to move them to the hardtop frame. I recommend having a convertible tranny crossmember installed so you get the distance between the rails correct and centered. Differing from 68-up. the 67 frame has double ears on each side for the crossmember, and has rear boxing pieces behind the rear wheels.

 

btw, all convertible frames in '67 were A. O. Smith so don't start with a Pontiac-vended frame. They are easy to tell apart. The latter has welded on pieces on the snout of the front crossmember, and for the front lower A arms. Also a weld joint in front of the rear wheels. Smith frames are all stamped with integral such pieces.

 

After doing some research I’m going to use the hardtop frame with the Hellwig kit. The way Hellwig designed the boxing section is actually stronger than a stock convertible frame and adds more rigid points.

 

Sorry, but as an aerospace engineer who's been designing structures for the last four decades, Helliwig is full of crap. First, don't confuse "strength" with "stiffness". These are two very different things. Strength is not the problem here, it's stiffness, specifically how much the frame deflects. Bending stiffness of a beam (like the side rails of a car frame) is a function of the cross section shape, area, and material properties. The larger the section in the direction of bending, the stiffer the beam is (this is why taller I-beams are stiffer). The parts of a beam that increase stiffness are primarily the top and bottom caps. The sides simply keep the top and bottom caps in place relative to each other. The Helliwig kit does not provide an increase in the top and bottom caps the way the factory convertible frame reinforcements do.

Torsional stiffness is similarly a function of the "box section" dimensions. The factory convertible reinforcements provide significantly greater torsional stiffness than do the Helliwig parts.

Sorry, you are mistaken. Don't believe marketing BS, especially when it comes from marketing people and not engineers. Once again, the engineers who designed the frame originally were not stupid.

I remain skeptical of a company who pushes those worthless diagonal braces to the front frame horns also.

 

It’s not a diagonal brace. It’s a boxed section that’s dam near exact as the convertible boxes are.

 

I was talking about this front stiffener that they also offer. I have yet to figure out what it's supposed to do.





Look, their current kit is better than others I've seen. It still isn't identical to the factory stiffeners. I'm not sure what that extra body mount does other than put loads into the body shell that it wasn't designed to carry. I can't tell you by looking at it if their kit provides the same stiffness as OEM or not. It isn't designed to replace a convertible frame, it's designed to provide the appearance of reinforcement for a hardtop. I don't know if their kit accepts the stock convertible trans crossmember or not, for example (their kit for the 68-72 cars definitely does NOT accept the stock crossmember, but the 64-67 kit isn't clear). Since it isn't exactly the same as the OEM reinforcements, the fuel and brake lines on the frame will likely require mods to fit. You've already got a convertible frame that you can probably harvest the reinforcements from. Your money, your call.

 

The drivers side factory box is weak. I’m going to measure , take photos, look at everything very careful before I do anything. Those front cross bars do nothing unless they are at the end of the rails.