How Do I Increase Fuel Mileage on a Ford 460 Motor?by Richard Rowe; Updated November 07, 2017
Items you will need
Full set of standard and metric sockets and wrenches
Full set of screwdrivers
Dial calipers and clearance measuring tools
Piston ring files
Standard and dead-blow hammers
Die grinder and porting kit
The Ford 460 is in many ways a dinosaur; its huge displacement made for big power, but it also made Ford's biggest of big-block engines an absolute pig at the pumps. However, there is some favorable news for those who want to have their 460 big-block and drive it, too. The 460 was designed from the outset to provide massive low-end torque (as opposed to high-end horsepower) for large truck and car applications, which does give it some potential as a gas saver when built to that end. However, you will have to start with a completely disassembled engine and build it up from scratch.
Building the Short Block
Purchase a set of slightly dished high-compression pistons--you want pistons whose compression rate will be between 9.5-to-1 and 10.5-to-1. The high-compression pistons will increase both horsepower and torque across the board without any real penalty in fuel consumption, albeit at the expense of a requirement for high-octane fuel. The dished piston will help to reduce "squish" velocity in the combustion chamber, giving the mixture more time to burn and express its power at low rpm.
Have the tops of the pistons coated with ceramic thermal coating. This coating will help to reduce thermal transfer into the engine's oil and the cooling system, keeping the heat energy inside the combustion chamber where it can do some good.
Port and polish the cylinder heads' exhaust passages to help used gases and heat escape. Use a die grinder to eliminate the casting ridges around the valve seats both inside the valve "pocket" (the area behind the valve) and on the combustion chamber roof. The intake porting will help to keep the fuel droplets suspended in the air for efficient burning, and the exhaust porting will remove hot waste gases quicker.
Coat the tops of the combustion chambers, the insides of the intake ports and the insides of the exhaust ports with the same ceramic coating you used on the piston tops. This unorthodox technique will go a long way toward keeping heat where it belongs: out of the cooling system and in the combustion chambers and exhaust where it can make power and enhance exhaust gas velocity, respectively.
Install an intake manifold with long runners designed to enhance low-end torque. The optimal solution for fuel economy would be electronic fuel injection and a tubular-style fabricated manifold, but that may prove prohibitively expensive. You could retrofit a throttle body and fuel injection system designed for a 1980s 454 Chevrolet truck, but it would obviously require some fabrication on your part. Installing a manifold with long runners is a logical approach, considering the complexity of your options.
Install a set of long-tube, full-race headers and a high-voltage ignition system with a multiple-spark ignition box and modern-design spark plugs. You might also want to consider using a set of roller-tip rocker arms (to reduce internal engine friction), an electric cooling fan and an electric water pump to reduce parasitic drag.
Building an engine for torque will not in and of itself improve fuel economy. You'll want to install either an overdrive transmission or extremely numerically low (under 3-to-1) rear-end gearing to keep the engine in its low-rpm sweet spot. You might do best to think of an engine such as this one as you would a diesel: it's a low-rpm tugger, not a high-rpm screamer. An engine built to these specs should make at least 425 horsepower and 550 pound-feet of torque.