Will these fit my 68 Barracuda?

No idea where to get them. At the suggestion of my local speed shop (this was in 1975) I took a regular set of aluminum spacers & cut the existing holes into slots so I could fit them on my car. Not the best solution but it worked for me at the time. Also held up well under a LOT of ABUSE on my part. Like launching the car throught the air on more than one occasion.