OldCorvetter

Help please. My midstyle's frame has never been good. I've found one close by, and have found enough info to confirm the year - so all that is good. BUT I found a couple sites that seemed to list a coupe frame as a different item than a convertible frame. I never thought there was a difference.

Anybody have some insight on this for me, I need to act fast to get the frame.

Thanks guys!

gbvette62

What year are you inquiring about? 63 frames are all the same, 64 and 65-67 convertible frames have an extra mount.

Nothing on a convertible frame, will prevent you from using it under a coupe body. When using a coupe frame under a convertible, you should add the extra mount back to the frame.

DansYellow66

If it's a good frame at a good price - grab it. The #2 mount issue is easy to deal with.

RestoMike

One more thing to consider, should your car be a BB '64 frames do not have the indent to account for the BB engine balancer.

OldCorvetter

Hi. Thanks so far. Yes, I knew about the dent for the balancer starting in '65, the recessess in the rear kickup rails for the rear sway bar as well, and the sometimes rusty famous keyhole slot in front of rear wheels to allow for the side exhaust mounting. But I don't know what or where this extra mount is for a convertible that you mention.

Can anyone tell me (preferably show me on a picture) where this extra mount is an what it does??

Here's a link to a 1964 frame picture, here on the forum:
http://forums.corvetteforum.com/c1-a...tte-frame.html

And here's a link to a 1967 corvette frame picture:
http://dynamiccorvettes.com/february-16-2011/

Can anyone sue these to show me where & what this is? A PM with a picture would be OK, or post something here. Thanks again.

JohnZ

Photo below shows the '64-'65 frame diagram - note the mount just forward of the end of the transmission crossmember where it says "867 only" - that's the #2 mount, used only on convertibles. It was welded to the frame at St. Louis on convertibles only, and is accessed through a hole in the sill, after removing the sill plate.

DansYellow66

The 64 frame doesn't have them and I couldn't tell if the 67 does or not. The convertible mount is about 15 to 18 inches (from memory) of the #1 mount at the firewall. The bolt is to secure it to the body is in the door sill under the sill plate.

I see JohnZ beat me with much better details.

OldCorvetter

Great job. Thank you. Based on your diagram, it looks like my picture below is definately a convert frame. I guess I'll be grinding off those brackets

Interesting your diagram for 64-65 doesn't denote the differences between the frames between 64 & 65: the depression for the balancer in the front cross member, and the narrowing of the real rails for the rear sway bar arms. Do you mind telling me where you got the diagram? I really like it.

Thanks again.

64Survivor

Hi, Can you tell me which part is called "the birdcage?" I have been asked to look to report the condition on a 64 I have for sale on the forum and would like to know if I will be able to give an honest look....after I figure out where it is. Thank you.

OldCorvetter

The birdcage is "none of the above". It's not part of the frame. It is the capsule of metal around you as you sit in the car to which your fiberglass is attached, that bolts to the frame. It starts at the rocker sills, goes up so that your door hinges have something to attach to, and turns into your windshield frame. You have a hard time seeing it most of it, as it is hidden by your interior trim, kickpanels, door hinges and the fiberglass that is bonded to it. The windshield frame is normally the worst for rust, you can also pull the kickpanels & you can look through the door hinge holes. Also look at the rear as it goes up and across the car behind you as well. It is what supports your door latch post.

Here's another post for your reference.

http://forums.corvetteforum.com/c3-g...-birdcage.html

Please don't turn this thread into a birdcage thread. I'd like to hear back from the 2 great guys that helped me out (above), and find out where that great diagram came from. I'd really like to buy them both a burger and a beer .... but we live a fair ways apart

64Survivor

I really appreciate that information. Will do the best I can to check the areas you mentioned. I didn't figure it would be like you described. No wonder the car rides so solidly. I guess since it was garage kept for over 40 years that should help.Thanks again. This forum.......is great!

AZDoug

Unless you are going NCRS, and if those brackets would deduct NCRS points, I would suggest leaving them if they do not interfere with a coupe body.

A quick gander at the design tells me they were added to make up for lack of an over the top birdcage on a convertible, to combat excessive body flex on a convertible, and would just give added strength to a coupe body.

Doug

mechron

WHY WHY Would you cut those brackets off. It is indeed a vert frame.
I have a 64 coupe, I fabbed up those brackets and welded them to my frame. The bird cage already has provisions for that mount under the sill plate. The 64 coupes get a bad rap. They have 10 mounting points. Everyboby forgets about the two body mounts at the rear of the driveshaft tunnel. Those vert brackets will give you twelve mounting points.

Sorry, but what is up with the later Big block C2s. They only had 8 mount points.

DansYellow66

I was thinking the same thing. I don't see what harm they can do and they are tucked away out of sight. Might even stiffen thinks up marginally to shim and bolt them down to the body.

JohnZ

You'll find that diagram in Section 2 of both the '64 and '65 Corvette Shop Manuals. It's for frame gaging dimensional references, so it doesn't show details that are unrelated to frame measuring/pulling dimensions.

The indentations in the '65-up rear rails are for caliper clearance at full rear suspension jounce.

Leave the brackets on the frame and use them for body mounts - it'll add some torsional stiffness to the coupe.

OldCorvetter

Thanks very much John! You helped a lot. I disagree about the indentations in the rear rails, however..... The indentations follow the exact contour of the rear sway bar arms that were implemented in 1965 for the 396 cars. Without that 1/2" indent the arms cannot travel between the frame and the tire. I've never had a clearance problem with putting disks on an early car, just sway bars. If you run across 63's or 64's with pockets fabricated into the rear frame rails for the sway bar arms.... I might have been the one that put them in there..... but that was a long time ago before anyone cared Thanks again.

A-Snake

I have to agree with JohnZ about the side indents on the frame. They are for caliper clearance. You may be thinking about the notch on the crossmember gusset.

TheSaint

Here is a picture of the birdcage

OldCorvetter

Well ..... OK.... or not . When you're run into the issues yourself and hauled out the grinders and welders to fix them, you sort of know when you're cutting a frame rail and when you're cutting a crossmember.

One day when you have nothing to do - try to fit a 9/16" sway bar around a 63 or 64 rear frame rails. Guess what ... the arms are too narrow and it will never fit. The eyebolts have no room to travel. You can save a bunch of time just using a tape measure, or just look at a big block car's rear bar & frame to see the situation, and how close the bar & bolts run to the indented frame.

Then I will send you a picture of a very nice 63 SWC doing autocross that's been running disks for 20 years with no frame mods (No rear sway bar though), and it's low and got lots of negative rear camper so you know the caliper is pointing it at the top toward the frame - no issues.

Either way, no mater who is right, I think this forum is great, and we're talking about fine issues on cars that we all seem to be fortunate enough to enjoy and know a little bit about them. Thanks for the info & discussion guys.

A-Snake

Sorry, I was referring to a 65/66 stock frame. I'm sure there are many modifications that can be made to retrofit later accessories to earlier frames. The first photo of a 66 frame shows the indented section of the frame I'm referring to that was to allow clearance for the calipers. If the indented frame was for a sway bar it wouldn't begin so far forward. ;-)
The second photo shows the (stock) notch I mentioned in the crossmember gusset that appears to be there to possibly allow clearance for the sway bar on BB cars. I'm not positive on this point, but why else would it be there?