Coolant overflow capacity?

clementine said
How many ounces are necessary for coolant expansion tank

2-3 cups

clementine said
What are you running for your coolant recovery

Not using coolant recovery. Using the top of the tank like the OEM designed it.

clementine said
What does the stock setup for a 67/8/9 383 barracuda look like? (I have asked google with surprisingly poor results so apologies

67-69 A body don't use a recovery system. You leave an air gap at the top of the tank about an inch.

If the coolant expands enough to puke some out, when it cools off it pulls in a little more air for the air gap at the top of the tank

clementine said
383 with a heater and 24.5” tank.

I drained the system and flushed. Then put in 3 gallons. In some of my research, I ran across the figure of allowing 12% of capacity.

3 x 128 x 0.12 = 46 ounces…. And that might be low on actual capacity of the entire system. Do I really need that much?

Not sure what you are trying to convey here