For Improved Fuel Economy (Mostly):
* Proper Maintenance is King: This is the single most important factor. Ensure everything is perfectly tuned and maintained:
* Tune-up: New plugs, wires, cap, rotor, air filter are essential. A professional tune-up including fuel injector cleaning/flow testing and throttle body cleaning can make a big difference.
* Oxygen Sensor: A faulty O2 sensor drastically impacts fuel efficiency. Replace if needed.
* Transmission Service: Fresh fluid and filter in the automatic transmission are crucial. Consider a fluid and filter change more often than the recommended interval.
* Tire Pressure: Maintain proper tire inflation – underinflation significantly reduces fuel economy.
* Alignment: Proper wheel alignment reduces friction and improves mileage.
* Check for Leaks: Look for vacuum leaks in the intake system – they severely impact performance and fuel efficiency.
* Drive Style: Gentle acceleration and maintaining a consistent speed on the highway dramatically improves fuel economy. Avoid jackrabbit starts and excessive braking.
* Weight Reduction: Remove any unnecessary weight from the truck. Every pound counts.
* Aerodynamics (Minor Impact): While not a huge factor on a truck, a shell or tonneau cover can slightly improve fuel economy at highway speeds.
For Improved Power (With Mileage Trade-offs):
* Performance Air Intake System: A cold air intake allows the engine to breathe more efficiently, improving power and throttle response. However, this often *slightly* reduces fuel economy at lower RPMs.
* Performance Exhaust System: Headers and a free-flowing exhaust system improve engine breathing at higher RPMs, increasing horsepower and torque. This will generally impact fuel economy negatively, but not drastically compared to other power mods.
* Upgrade the TBI System (Moderate to Significant Cost and Effort): Consider a performance TBI system or a complete upgrade to fuel injection (e.g., carburetor swap or aftermarket EFI conversion – this is expensive and complex). These options have the potential for significant power gains but at a cost of increased fuel consumption.
Things to Avoid (Generally Counterproductive):
* Large Engine Swaps: Swapping to a larger engine is expensive and complex. While it would dramatically increase power, the fuel economy hit would likely be significant.
* Forced Induction (Turbo/Supercharger): These systems are very expensive and complex for a 305 TBI and will substantially reduce fuel efficiency while producing significant power gains.
Realistic Expectations:
With a 305 in a K1500, significant power gains will always come at the expense of fuel economy. Focus on one or the other. If you want better fuel economy, concentrate on maintenance and driving style. If you want more power, you'll need to accept some reduction in fuel efficiency, and some modifications are likely to be costly.
Before making any modifications:
* Consult a Mechanic: Discuss your goals with a knowledgeable mechanic specializing in older GM vehicles. They can advise on what modifications are feasible and cost-effective for your truck and its current condition.
Remember, a well-maintained engine will always perform better and more efficiently than a neglected one. Start with the basics – proper maintenance – before considering more expensive performance upgrades.
