What are these M10 holes for?

[BlackZR1]

Looking up at the bottom of my car just inboard of the front jacking points on both sides of car I see these 4 - M10 tapped holes on a 1" x 3" pattern. (See pic) Anyone know the purpose? Maybe a chassis stiffener mount for convertible cars?

I was thinking of making a couple of 1" thick 6" x 3" UHMW pads to mount there for better lifting / jack stand contact area.

Thanks,
Roger

[aafc]

Holes were/are for x-brace or frame connectors from vette to vette
John
1990 white /black #2546
one of a few auto (4l80E ) eq. ZR-1's

[WVZR-1]

Looking up at the bottom of my car just inboard of the front jacking points on both sides of car I see these 4 - M10 tapped holes on a 1" x 3" pattern. (See pic) Anyone know the purpose? Maybe a chassis stiffener mount for convertible cars?

I was thinking of making a couple of 1" thick 6" x 3" UHMW pads to mount there for better lifting / jack stand contact area.

Thanks,
Roger

Look in the FSM section 10-3-8 or so (varies with year) and there should be an image that might satisfy your curiosity!

[BlackZR1]

Look in the FSM section 10-3-8 or so (varies with year) and there should be an image that might satisfy your curiosity!

My underbody braces are missing!!!
Why would anybody remove them?
Maybe to make room for the Borla exhaust?
I'll get under there again tomorrow to see what's going on.
I am not happy, but thanks WVZR-1 for pointing that out.

Thanks,
Roger

[Kevin]

My underbody braces are missing!!!
Why would anybody remove them?
Maybe to make room for the Borla exhaust?
I'll get under there again tomorrow to see what's going on.
I am not happy, but thanks WVZR-1 for pointing that out.

Thanks,
Roger

Roger,
The x-brace was a convertible only add on. You're not missing anything

[BlackZR1]

Roger,
The x-brace was a convertible only add on. You're not missing anything

Thanks Kevin.
Back to my original plan then.

Roger

[Kevin]

Thanks Kevin.
Back to my original plan then.

Roger

If you were looking to get a frame stiffener I'd go with https://www.vette2vette.com/?q=productdisplay/86-96-c4-no-flex-frame-stiffener-bar-system-5

I have one in the garage, just need a lift to instal it

[RussMcB]

I was thinking of making a couple of 1" thick 6" x 3" UHMW pads to mount there for better lifting / jack stand contact area.That's a clever idea, Roger.

I've heard of something similar, from Miata racers. They buy hockey pucks on ebay and bolt them to the frame welds for jacking points.

[Fully Vetted]

If you were looking to get a frame stiffener I'd go with https://www.vette2vette.com/?q=productdisplay/86-96-c4-no-flex-frame-stiffener-bar-system-5

I have one in the garage, just need a lift to instal it

It can def be done without a lift. I did mine in about 1 1/2 hours. An hour for the first side and 30 mins for the second.

[Kevin]

It can def be done without a lift. I did mine in about 1 1/2 hours. An hour for the first side and 30 mins for the second.

you're a braver man then I am. Maybe I can talk a few guys into doing it at carlise for me ;)

[Fully Vetted]

You'll need to remove the rear wheel so a jack and jackstand is needed but honestly you're not even under the car. If it wasn't for needing to drill that one hole (which is why you have to remove the wheel) you could almost do it with it on the ground.

[Kevin]

You'll need to remove the rear wheel so a jack and jackstand is needed but honestly you're not even under the car. If it wasn't for needing to drill that one hole (which is why you have to remove the wheel) you could almost do it with it on the ground.

the prototypes didn't have the hole drilled, I was considering not doing it. I've had these things sitting in my garage for a year tomorrow. Bought them at carlise last year. Wife's banned me from buying more stuff till I install these...I need to get on it

[BlackZR1]

If you were looking to get a frame stiffener I'd go with https://www.vette2vette.com/?q=productdisplay/86-96-c4-no-flex-frame-stiffener-bar-system-5

I have one in the garage, just need a lift to instal it

That's a nice kit Kevin. Looks well made. A bit pricey though.
Description says "does not require any body modifications to install. The system bolts to existing mounting holes with the supplied hardware"

Roger

[Fully Vetted]

You're right. My bad. I thought I remembered having to drill a hole. Actually it's a bracket you have to replace with the supplied bracket. Again, the only reason for having to take off the wheel is to gain access to that bracket. Still, it's a piece of cake mod.

[BlackZR1]

That's a clever idea, Roger.

I've heard of something similar, from Miata racers. They buy hockey pucks on ebay and bolt them to the frame welds for jacking points.

Simple project is complete. Easy target for jack and large surface for jack stands. Avoids contact with fuel lines.

Roger