Took the Barracuda to the track today for first time

70aarcuda said
check jetting in carb....valve springs???

I agree and will add, fuel delivery issues or possible ignition problems.

If it's dieing under load, sounds like fuel to me.

That should be a solid 12 second ride with a 101 MPH not pulling above 5K. It's likely missing 3-5 mph. 60' is pretty darn good for first time out.