The P255/60R15 tires were not exclusive to the Pace Car edition.  These tires were option code QBS which specified "White Letter SBR tires, P255/60R15" and option was for a set of four.  For 1978, Chevrolet released 6,502 Pace Car editions, one per dealer.  However, the actual quantities of option QBS  was 18,296 sets which is 39.1% of all 1978 Corvettes produced.  See below (will need to scroll left & right to see the entire chart):

Okay, so you don't have to 'scroll'.  Appeared that way at first in the message body box.  My bad..... 

Still curious as to what the 225/70 tires were.

Think I have an answer to F4Gary's post about what the P225/70R15's were. 

I posted the question about what brand/model of tire were the P225's on Corvette Forum.  One of their members replied.

The answer is:

Goodyear P225/70-R15 Polysteel

Raised White Letter - Small Letters

“See what’s new today in a Chevrolet.” A subtle opening of the doors for the Corvette Silver Anniversary edition. For this presentation Goodyear rolled out the red carpet – with deep pile. The Goodyear Polysteel Radial.P225/70-R15 Small Letter Goodyear Polysteel Radial RWL P225/70-R15 Large Letter Goodyear Polysteel Radial RWL Goodyear Polysteel – a Corvette tradition. Simply performance to the nth degree. Once again, ride with authentic pleasure. Ride with Goodyear Polysteel. Simply eye catchers by any definition.

Construction: Side wall - 2 Plies Polyester Tread – 2 Plies Polyester, 2 Plies Steel, 1 Ply Nylon

Original Equipment Years: 1978

 

That's what I was looking for!👍

So those 20+ year old Goodyear STs are pretty much worthless.

I did sell some 20 year old Polyglass tires at the swap meet here, but the buyer only wanted them so he could roll his chassis around in the garage while he worked on it.

Hey Pat my name is Terril Fugitt and I’m interested in your tires. Do you still have them if so I probably want them.

Never mind they are the wrong size

Are you still sitting on the ST'S???

Terril, you do know they are not road-worthy tires, right?

I no longer have the tires.