bellaireroad

Are these the grounding straps for the exhaust? If so, is the frame drilled for the strap attaching bolt on a factory side exhaust car?

GPGG70

Good question. Yes those are the exhaust ground straps for the rear exhaust.
As for the side exhaust for 69 only, I would say yes the holes where drilled before arriving at the GM plant. A.O. Smith built the frames for GM, then stock piled them up out in the rear area of the plant. The GM workers would go out and grab as many as there fork lift could carry. From what I read in the past there was no seperation of the frames.
So when the frames went down the assembly line in 69 for the side exhaust optioned vettes, they would not hook them up with the grounding straps, just leaving the holes open.

Alan 71

Hi ba,
I believe the holes are there on all frames.
An original side-exhaust car will have holes but won't have threads cut into them from the ground strap attaching bolts.
There's always the chance though that the car left St.Louis with under car exhaust and threaded holes, but the pipes were added, and then the holes were welded closed and re-drilled so they don't show any threads.
This is an example of why all the factors used to determine an original side-exhaust car need to be verified.
Regards,
Alan

AdamMeh

So, grounding straps on the exhaust? I understand what grounds are for, but what was the reason for grounds to be placed on the exhaust? I know for a fact our '77 does not have these (currently) - the holes may be there as I was not looking for that while under the car.

Adam

Easy Mike

Yes. Your AIM will show them in the optional radio section.

Alan 71

Hi,
I believe the exhaust ground straps have to do with preventing radio static interference.
When the RFI shield was added to the distributor in 1971 it seems the exhaust ground straps were cancelled.
Is this somehow also hooked to the change in the distributor cover from 70 to 71?
Very Confused?!
Regards,
Alan

Easy Mike

Good point. Later cars may not have them. Earlier cars certainly did.

gbvette62

Correct, 1970 was the last year that the factory put ground straps on the exhaust.

Corvettes did continue to use some ground straps after 70, on places such as the antenna ground plate, but not on the exhaust pipes.

GPGG70

Just a added tid bit. Today I was working on the coupe and noticed the rear of the frame had the holes drilled and tapped for a rear stabilizer bar. Seeing this reminded me of this thread, only in a slightly different aspect. I've noticed them before but paid no mind to them. Also it looks like they where filled with a type of buthal putty like on the firewall. My coupe is a 350 small block with the original frame. So now did all the frames come with a pre-drilled holes for stabilizer bars even though they where not big blocks. Anyway thought I throw in this bit of info.

Alan 71

Hi gp,
My 71 sb, std suspension, frame, has the required holes drilled for mounting a rear sway bar.
Regards,
Alan

Easy Mike

Yes. There is no difference between a big block and small block frame. Rear stabilizers were part of the gymkhana F41/FE7 optional suspension package which could be ordered with small block cars.

AirborneSilva

So then can I infer that if my 76 has a rear anti sway bar it is a gymkhana suspension?

joewill

keep in mind that only 4355 out of well over half a million C3 cars left the factory with side exhaust. don't be too sure about the hole drilling theory. There is an engine to frame ground cable up by the starter that would surely pass all the ground current needed to properly ground the circuit path. mine was broken for years and the car ran and started fine. the current will find a path to ground if there is one.

gbvette62

Gymkhana included a rear sway bar, a 7 leaf rear spring (standard suspension has a 9 leaf spring), different front coil springs and heavy duty shocks.

It's not possible to identify the coils visually, but they would have had a paper tag with a 2 letter code on them when new that identified them. All of the OEM Delco shocks pretty much look the same, the only difference would have been the part numbers. I may have the part numbers around somewhere.

AirborneSilva

Cool, guess I'll be counting leaf's this weekend Thank you for the info