"several Mustangs and Thunderbolts had engine failures early on."
I am not aware of R-2800 engine failures.
I know the new fuel proved very problematic for the P-51's and to a lesser extent, P-38's and Thunderbolts. There were parallel tests of the new fuel with all three aircraft and the Thunderbolt (now rated at 2,600hp) suffered the fewest issues. (overheating at 70Hg in sustained climbs was one).The Mustangs had their plugs constantly fouling and their maintenance schedules had to be significantly shortened.
I am not aware of R-2800 engine failures.
I know the new fuel proved very problematic for the P-51's and to a lesser extent, P-38's and Thunderbolts. There were parallel tests of the new fuel with all three aircraft and the Thunderbolt (now rated at 2,600hp) suffered the fewest issues. (overheating at 70Hg in sustained climbs was one).The Mustangs had their plugs constantly fouling and their maintenance schedules had to be significantly shortened.