List your MPG on your transplant 5.7 or 6.1

64 Polara 500, stockish 5.7, Tti headers, Tti full exhaust with x pipe, 8 3/4 with 3.91's, 545rfe trans (stock), Diablo canned 91 octane tune, vintage air ac/heat, and so far the best mpg is 19.