Originally Posted by TC@HP2
Originally Posted by mopartruckguy
Who has some real world numbers from a 4x4 with 33"/35" tires and a 440 with 400+ HP. What could a fellow expect the mileage to be on a motor of this caliber?


Not enough info to quote accurately, but I'd guess somewhere between 5-8.

Once upon a time I had a 440 in a D200 crew cabwith 4.10s and 33" tires that would knock down low-mid teens in town and high teens on the highway. Engine was built not for horsepower but for torque and was all in by 3500 with a redline of no more than 5000. It was a pretty basic build; balanced, almost blueprinted, around 11:1 compression, performer intake, Ebrock carb, small cam, and a lot of thermal barrier and dry lube coating throughout the engine.

The 11:1 worked great where I live at 6500' elevation. It also was a beast pulling over mountain passes in the 10,000' range as well. I could pass traffic with a loaded trailer. However, it was a big problem at lower elevations. A trip to Phoenix once was detonation city and it was drinking octane boost like nobodie's business. I built a replacement for it that was down a couple points on compression and it also was down on mileage and power, but it would live at lower elevations.

In hindsight, methanol injection on the higher squeeze motor would have been a good addition to help with lower elevation issues, but I never got around to it. This engine is still sitting in my garage on a stand. I've been thinking of a larger cam to offset the high compression would be nice, and drop it into something lighter weight than a truck.


With the engine on your stand I would seriously consider retarding the cam a few or 10 degrees to bleed off compression and a little reversion back up the intake will help mix the air and fuel better, lastly it will give the burned air and fuel more time to press down on the piston before the exhaust valve opens and lets the pressure out, this is the expansion ratio and the theory is that this is even more important than the compression ratio, sort of like an atkins cycle engine.


I am not causing global warming, I am just trying to hold off a impending Ice Age!