I have a choice between which engine I can put in my truck I was wondering what would a 78' F150 with a automatic get for gas mileage if it had 360, 390, 351m, and 400m in it? Also what is the horse power and torque rating of these four engines?Also what is the most reliable engine of the four?

 

I have a '70 F100 with a 390 C6, 3.50 gears, and a two barrel carb. My truck weighs 4100 lbs with a full tank of gas. It gets eight to 15 miles per gallon, depending on what I'm doing. Reliability? In the 80,000 miles I've owned it(for a total of 160,000 miles), I've replaced the timing gears and chain, camshaft(due to timing chain and nylon gears), two burnt exhaust valves, 56 spark plugs, three wire sets, 40 gallons of oil, and 32 oil filters. I think it's pretty reliable!

 

390fe,
I'm sure glad to see ya keep good maintance records.
What would you think would be the tallest gear
I could run with my 65, 240-6 with 3 speed?

 

It has 275 horse and about 400 ft/lbs torque from the factory.