I am in the early stages of a complete rebuild of a 69 coupe. The front clip was off the car and broken as I received it and I knew I was missing several structural parts at the front of the car. To date I have stripped and painted the frame, which is in very good condition, and have completely rebuilt the suspension, brakes, steering, differential, installed a newly rebuilt motor etc. In order to run the motor up to temp before tackling the body I recently acquired new front frame extensions, cross member and a radiator frame for a 26" copper radiator. My first hint at a mismatch was the bumper bracket holes on the frame extensions do not line up with the attachment points on the frame. Why I hadn't done this before I can't say but knowing the 68 frame extensions were different I checked the serial number on the frame and confirmed I have a 68 frame. I had previously verified the motor, body tag etc match but hadn't checked the frame since pulling the body off the car. I made the decision to stay with the '69 frame extensions and move the bumper bracket mounting to ensure I could use 69 specific parts throughout the rest of the front reconstruction. My next hit was the lower LH radiator bracket was slightly contacting the tip of the frame. This issue I fixed by cutting a small notch in the lower frame flange. Then when tried to install the radiator in the support frame I found a significant interference on both sides where the clearance between the radiator support frame and the frame rails is not enough to accommodate the depth of the radiator outlet tank. It looks like I would have to cut around an inch off the tip of the frame rails to fit. I've tried to find a couple of good pictures of 69 and later frame rails. I haven't found many that were absolutely clear but the ones I've found seem to show the frame tips on the 69-71 are a little shorter than the 68. Before I go after the frame with a cut off wheel I'm hoping someone can confirm this is the case.

 

Post pics of your frame. Essentially, the 68 and 69 frames are the same with the exception the early 68 frames did not have the add on rear support the later frames received.

 

 

Yes, I can verify that you will need to trim the front of the 68 frame to install a 69+ radiator support and 69+ radiator.

I have installed 3 different 69+ radiators/radiator supports in 68 frame Corvettes to gain the larger radiator of the 69+ Corvette design. I want to remember more trimming was required for the wider BB radiator outlet pipe than the SB a/c radiator, but still both needed trimming.

You will also need to drill holes for the 2 large bottom bolts in the 68 front frame Vee support to the 69+ radiator support. And the front bolt on extensions are different for 69+ vrs 68. So you have to redrill holes to attach or get 69+ frame extensions. I highly suggest you measure the distance from the floor to the nose of the Corvette before taking it all apart so that you will know what to shoot for after modifications (too late?).

And you will need to make a passage in the LF fender shirt to route the wires from the engine bay to the front headlights/horns since the 68 radiator support has a wire passage but the 69+ does not. The 69+ LF inner fender skirt has a passage molded in. I cut holes in the 68 skirt and make a sheet metal cover for the wires.

All doable with some nominal work and worthwhile IMO to gain the benefits of the larger 69+ radiator.

Nice work! and Hope this helps.

 

Yes, it does. The reference to the larger core makes sense. Only the frame is 68 so everything else is or will be 69.

 

That should be your only issue. The 68 had the radiator inboard of he frame and the early 68s didnt have the rar kick up supports. They also used solid body mounts. As long as you have a 69 radiator support you should be able to make it work and you will be able to see the diferences

 

I just remembered an additional difference between a 68,69 frame. 69 Up frames have a bracket welded to the frame roughly under the master cylinder for the changed position of the brake pressure monitor block. On 68's it is connected to and under the master cylinder. Lou.

 

i

in 69 the brake pressure block was attached to the bracket and just screwed to the frame, so no welded bracket to frame
also all 68-72s had solid body mounts

 

I bought a GM replacement frame for my 68. The frame fit 1968-1974 cars and that bracket was welded on. I thought all of them were welded on. Lou.

 

that's possible Lou, perhaps the 73 and up frame has the welded bracket because the proportioning valve is different on 73 and up

 

Thanks for the responses. I also have an early 68 frame because it does not have the additional bracing at the rear kick up. What's the consensus on the additional bracing? I'm not that concerned about originality at this point. I can add them for $100/side or assume its good enough for a car that's going to see weekend jaunts arounds the country side only.

 

Its stiffens up the frame and keeps the frame and body from flexing. They started adding them late in the 68 run and all the frames after that have them. A stiff frame makes a better riding and handling car