69 GTO Convertible Frame
 

Hi all,

My friend is trying to rectify some shoddy work done by the PO of his 69 GTO convertible. He took it to a reputable restoration shop and got a load of bad news. 1st up, the frame is twisted and therefore needs to be replaced. As this thing sounds like a frankenmobile, does the convertible have a different frame from a hard top? Figured it might and there might be an incorrect frame under the car.

Yes two different frames. Convertible is boxed and the HT is open. I believe the best way to check the frame is it should be put on a frame table and measured, unless you see it was in a wreck or rusted out. Good Luck, Marc.

just curious how twisted a frame needs to be to warrant replacement.
Many a 69 frame has been put back in shape on a good frame machine.
Heck Ive used many unorthodox methods to get them straight.
Big trees,chains,come a longs,heavy equipment,if done correctly will suffice.

If the repairs or straightening needed was extensive or unreasonable. I think I’d be tempted to replace with one of the aftermarket frames available.

Eg. Roadster shop frames start at $13,000, that would be a great foundation to build a nice convertible on.

I wondered the same thing myself but the way this thing drives (I drove it), it's a real mess, almost dangerous. That's why I was questioning what is underneath. While the frame, suspensions & engine are a mess, the body itself is gorgeous.

a simple string and plumbob can tell a lot in just a few minutes

My 69 Lemans convertible has apparently been hit in the front and maybe the rear as well. The frame was bent in more than one way. Additionally, when I was troubleshooting how bad it was, my measurements did not make sense. I had the body off and the suspension assembled with wheels and tires. The wheelbase on each side didn't match the frame measurement deviation. Then I looked down at the rear axle and it was visibly bent! The previous owner had been driving it that way.
Anyway, I found a shop who agreed to straighten the frame for $800 (in 2015). Good luck, none of the other collision shops wanted the cash business, they are setup to do insurance work. This shop was a friend of a friend and that's the only reason they were interested.
I am pleased with the end result. Make sure they check and fix the front extensions or the radiator support won't line up.

if you do replace the frame- be sure to get a 2 door frame. the 4 door, station wagon and el camino ones look similar but have a longer wheelbase. It’s possible to cut and weld it to size but more work involved. Fab skills vs time/ money, etc. many posts online about this subject. Also, should you locate a 2 door hardtop frame as mentioned it won’t have the boxed rails which would be more critical for a convertible as it lacks the body structure but there are kits out there to reinforce these frames as the factory convertible ones seem to command a higher price. it might be cheaper to go this route. an example of a reinforcement kit: https://www.opgi.com/chassis-suspens...r-ch30614.html hope this is helpful

btw, good news is that basically any 2 door (112" wheelbase) 68-72 A body frame will fit regardless of GM division. As mentioned, convertible frames are dimensionally identical to the other 2 door frames but had boxed side rails that were factory welded to a coupe frame C sections. Convertible frame also has heavier section over the rear axle. Inversely the door 2dr post sedan frame looks the same as the hardtop one but has thinner sections in some parts of the frame.