A-Body frame question

[Ummgawa]

Is the frame on a 70 Chevelle,GTO,442, GS coupe the same as a convertible frame for the same A-Body models?

Any additional bracing for the Convertibles? any pix for reference?

[ottatyme]

Originally Posted by Ummgawa

Is the frame on a 70 Chevelle,GTO,442, GS coupe the same as a convertible frame for the same A-Body models?

Any additional bracing for the Convertibles? any pix for reference?

I'll try to get into some boxes (yeah, still unpacking from the move) to find proof, but if memory serves correct, the convertibles had boxed center rails, where the coupes do not....

[comp-spec]

The frame is the same but they box in the centers of the frame rails

[hectore3]

This is correct the convertibles are a bit boxed. Have a welder weld up your coupe "C channels". And if you add a cage it will be the more stiff. I am planning on using POR-15 on the frame welds for corrosion resistance also. Good luck on your project!

[dav8427]

The earlier a-bodies had a extra set of body mounts.(16 vs. 14)
Not sure about the later ones.
I believe a Elky frame is boxed and can be made to work if you shorten the rear portion.

[Blown353]

Convertible frames are dimensionally interchangeable with Coupe frames with the following exceptions:

1. Convertible frames are boxed under the passenger compartment and use a different tranny crossmember, fuel line set, and front to rear brake line.
2. The two bodymounts at the mid-door level on a convertible frame have bottom bushings and thru-bolts while the factory Coupe configuration is just a floating bushing on the top. This isn't so much a frame difference but an assembly line difference; coupe bodies have nutplates in the bodies in this position and you can add additional bottom bodymounts and bolts here and get some extra stiffness.
3. Convertible frames use two additional body bushings up front under the cowl.

Elky/Wagon/4 door frames are also boxed. However 68-72 versions have a longer wheelbase than two doors-- the stretch is done in the center. Elky frames also have a longer rear section. The rear section is easy to chop and shorten but taking the extra wheelbase out of the center is much trickier not to warp things.

Best bet is to either find a complete convertible frame (often very expensive) or just to box your existing (or another) coupe frame.

[Derek69SS]

Originally Posted by Blown353

Elky/Wagon/4 door frames are also boxed. However 68-72 versions have a longer wheelbase than two doors-- the stretch is done in the center. Elky frames also have a longer rear section. The rear section is easy to chop and shorten but taking the extra wheelbase out of the center is much trickier not to warp things.

Wagons and 4-doors are not boxed, only El Caminos and Convertibles have boxed frames.

Wagons, 4-doors, and El Caminos are 4" longer in the middle than coupe/convert frames

Wagons and El Caminos are 6-1/4" longer in the rear, and the rear of the frame is shaped different (flat instead of curving up at the rear)

They are the same from 68-72, so this will have all the same dimensions...

[Ummgawa]

Thanks everyone and thanks Derek, Thats exactly what I was hunting.