The first mileage test results are in.
A quick review of what was done to the truck.
Cometic head gaskets half the thickness of Fel-Pro and with full o-rings around each cylinder, not combining into one ring between cylinders like Fel-Pro. This raised all compressions from 185 to 200, to 200 to 220. ARP head studs at true 90 pounds torque instead of garbage unreliable twist to yield factory head bolts. New Melling timing chains, tensioners, chain guides and Melling 176 HV high volume oil pump with lower pressure spring installed. Porting out the exhaust ports to gasket match the new headers. A pair of Gibson 1-1/2" ss tube headers. SPD Performance Y-Pipe modification to exhaust creating better flow and scavaging. The MMR Racing coolant adaptors to the backs of the heads and plumbing them into the coolant return tube to the water pump for better cooling. Fabricating a larger 3-1/2" cold air inlet. Removing the comb like teeth in the throttlebody intake gasket improving intake air flow again. Welding shut the unused rear of head intake manifold coolant passages to prevent leaking due to the cheap plastic stock intake manifold. Modifying the intake manifold crossover tube connections to improve sealing and reduce the chance of the common leakage problem from happening again. Using the crossover clamp device I thought up to further increase the likelihood of a permanent seal. The injectors are 1 year old and all NGK ignition coils are 8 months. Several sensors were also replaced, MAF, O2 L & O2 R, TPS. All sensors about 6 months ago.
Ok, so what are the mileage test results?
After 140 miles of mixed city, arterial, freeway driving, the resulting MPG is 11.75
11.75 MPG may or may not impress people but, it is a 2000 F-250 super cab 4x4 with a 5.4 liter 2 valve engine and 4 speed automatic. Before, we were getting 8 or 9 mpg, "10 on a really good day without the TC on".
This represents an improvement of 3 to even 4 mpg. That will add up to decent savings over time. I just need to stay on top of maintenance to keep it this way. Regular oil changes at 3000 miles or less are very important, especially if you drive a truck with the 3 valve engine.
Everything I did to the engine, is on video and was posted to this forum if you're interested.
Thats the end of the truck repair/improvement video series. I hope those who saw it, enjoyed it. And now you know the fruition, end result.
It's back to camping soon.
