There is just more to it than a duration #.
Cam profiles at .050, is one measurement point of the whole lobe.
Lets say someone answers your question and says 276* @ 050. There's hundreds of different lobe designs with that degree @ .050. But what about at .006, .100, .200, .300,.400 etc etc. This will all factor in. If you want a cam that will work with your particluar combo, you will need to talk with a few reputable cam companies. And not the yahoos' @ the cam help line at comp. Unless you can get a real cam tech on the phone. Maybe try calling a few and see what they say.
Bullet cams, Cammotion, Reed Cams, Camdynamics.
On your Chevelles site post. UDHarold that posted a reply to your thread is one of the best in the business also.
He designed the Ultradyne Cams that Bullet is now using a lot of,
Worked for Lunati and designed the VooDoo series.
Worked for CustomCamshaftCo. and came up with some more stuff.
What was the 60ft on your pass. 572 inches should pull pretty hard even overcammed and understalled I would think?