MY SON IN-LAW AND I ARE ABOUT TO PUT A V-8 IN HIS 94 4X4 EXT. CAB. WE ARE PUTING TOGETHER A 327 C.I. FOR GAS MILAGE & PULLING THE LIKE'S OF A SMALL ATV TRAILER. I USE TO HAVE A 65 VETTE AND GOT GREAT GAS MILAGE WITHA 600 HOLLEY , FIGURE IT CAN'T BE ANY WORSE THAN THE 4.3,PLUS A LOT MORE POWER, I HAVE NEVER SEEN A 350 GET NEAR THE MILAGE AS A 327 DOES.