We had just finished installing a 440 in my friends' '65 Coronet. We pulled his 383 that ran a best of 12.5 something. Using the same cam, heads, carb, headers and drivetrain, we were looking for at least a .5 decrease in ET. The car ran the same as with the 383. We picked up .3 only when we dropped the exhaust at the collectors. It has a 3500 stall converter, 4.30 gears and 28" tall slick. The car launches a lot better, but seems to slow down from around half track on. I'm thinking this thing should be 60'ing in the low 1.6 range instead of 1.7-1.8 and running at least low 12's to high 11's. Any suggestions?