Ram runner has a 5.9 liter magnum swap, with EFI. The engine and trans came from the same totaled Ram truck, so I spliced into the TPS wiring. The EFI has since been upgraded to FAST EZ EFI, and I again spliced into the TPS wiring, and bought the FAST throttle return/cable bracket along with the 700r4 TV cable bracket. Works great.That's a good choice of product, how did you accomplish the TPS and TV cable on your carb/throttle body?
I agree with Greg. Leave it. From a financial point of view, how long will it take to payback what you spent by only getting 2 or 3 mile per gallon more than what you currently get? Is this your daily driver? Do you put 15,000 to 20,000 miles a year on it? If you were to drive 15,000 miles per year @15mpg and @$2.50/gal, it will cost you $2500 in gas. Same conditions @18mpg, it will cost you $2082.50, saving only $417.50 per year, not worth it in my opinion. My dad wanted to do the same conversion to his Dart and he only drives it 3,000 to 4,000 per year and once I showed him this comparison, he said never, he'd rather do something else to the car. Just my opinion.
Your calculator is way off. You better review some math.It would depend on your final drive ratio but for example a car with a 2.94 rear end ratio and 26.5 inch tall tire will be at 2600 rpm at 70mph plus a small amount of converter slip. If you have a mechanical fan with no clutch it can really sound like the engine is screaming even at that rpm but it isn't. In fact, using an overdrive with a .70 4th gear ratio will drop rpm at 70mph with this same combination to 1800 rpm. While that looks good on paper, consider the aerodynamics of our old cars and the fact that a small engine does not produce much torque or horsepower at such a low rpm. Your engine will be struggling at that rpm to move the car through the wind at that speed, it may end up using more fuel at this rate of operation than it would have stock.