[ACE-OF-ACES]

The increase in manifold pressure will most likely raise the powerplants critical altitude but I dont believe that you will see a significant increase in power output

belive..

http://www.wwiiaircraftperformance.org/p...28392.html
Flight test have been conducted at Wright Field on the P-38J-15 Airplane, AAF, No. 28392 at the request of the Power Plant Laboratory, Engineering Division. These tests were made to determine the increased performance of the airplane using the higher powers allowable by the use of 44-1 fuel as compared with the powers allowable with the standard fuel, grade 100/130

S!