I am totally beside myself!! While putting my freshly reconditioned control arms in on the passenger side of the car, I noticed a crack in the frame, just forward of the motor mount . It's open at the bottom maybe 1/16" and travels 2/3 the way toward the top of the frame.

At least you found it that way, and not the hard way!
I've seen a lot of 'Vettes with cracked frames, mostly around the suspension points, and on the driver side, where the steering rod bolts thru the bracket. You may also find some cracks in the welds at the lower control arm attatchments, as these were not welded all that well to begin with. Now would be the time to go over all of the welds in the front frame, and make sure they are stable.

  My drivers lower control arm tore out the second day I had my car,,,,Had it welded and reinforced and haven't had a problem since...And that was 20 years ago....Still looked fine when I rebuilt the front end 3 years ago and I check it every time I change the oil.......You should be ok after the repair. From what I have been told, GM cars from the 60's and 70's had this as a common problem.......

Paul since you found this one don't you think you should check the whole frame? Joel, what about the stuff you spray it on and the cracks show up?

[QUOTE=spielman5] Joel, what about the stuff you spray it on and the cracks show up?[/QUOTE]

HUH?
Never have I heered of it, unless you be talkin aboot sandblasting? (or talcum powder)     

Welcome to the club.  The day I went to pick mine up, the price dropped almost $3K due to the power steering arm attach point falling free of the car. Fortunately, I could weld and had a buddy that I Huck Finned into doing the upside down parts (because he is obviously such a much better welder than I HA/HA).

When the bullet came out, I found cracks both laterally down the frame and around the crossmember.

When doing the front suspension, I thought I had them all with the cracks up into the spring pockets.

They never end. 

There is a penetrant die (zyglote or magnaflux?) I remember from my airplane shop days that will show up cracks non-destructively but I don't know if it is available to the average consumer.

Good Luck!

Joel, Magnaflux system..Here is the website.. spielman52006-12-04 09:04:50

Tanks!!

Paul, you have my sympathies--on one of my early trips 'down under' to acquaint myself with the half of the car that I couldn't inspect on my feet, I too found a crack in the left front suspension. What looked like a pretty big one to me, for that matter. And I had that same, sinking feeling I know you experienced. Makes you feel as though it's mortally wounded, and can only get worse.

But thanks to the gang here, and some extensive scouring for info elsewhere, I finally calmed down and understood that these cars are very prone to this--and it's repairable.

Still, I hate having it there--and it makes me all the more hyper to examine/re-examine every last square inch of metal that I can see.

So I hope you get yours sorted out to your satisfaction/relief. At least we're not alone, by any stretch!