Right now the truck has a 350, I know 350's, have driven 350 powered vehicles since I started driving. As my Sig states, I am an unconventional thinker. The 350 in this truck gets 13 to 5 mpg's. I can cruise at 3,000 rpms all day long and get 12 in this truck, but you're only going 50-55 with the 4.57's. Tires are 31.7 inch diameter. Overdrive engaged(30%), average is 13 mpg while cruising around 70-75 mph, but the 350 doesn't like the 3.19 final drive gear on anything but flat, downhill, or downwind so the inclines and headwinds make it get 5-ish mpg.
The goal is to have torque, not high revs. I don't rev my engines over 3,000 unless it's by accident. I have never had an I6 engine in anything but my Cherokee, and to be quite honest, it has plenty of power. It'll cruise at 70 turning about 2,100 rpm's in OD (2.66 final drive in 25% OD) and gets 20-22 mpg's at that speed. My truck weighs less than the Cherokee, go figure, yet sports similar boxy non-aerodynamics. The truck will have similar gearing (2.58 final drive in 27% OD) as the Cherokee when it's all said and done. Will I expect 20-22 mpg from the truck? No. Would it be nice? Yes.
To make the 292 more efficient by allowing it to breathe better with better exhaust and better intake, not over carb it, and get the gearing to be at the sweet spot of the torque curve is ideal. The truck will be used as a truck, but still be able to cruise down the road without over revving.
I'm not looking for LS power, don't want it, don't need it, wouldn't go that route if you paid me to. I like my old rigs to retain as many of the factory pieces it left the assembly line with, and in this case, an engine option that was available from the factory. I want torque, these engines are made for torque, and I believe from the reading I've done that I can get the torque at a better spot instead of peaking at 1,600 rpms according to the shop manual, and possibly get better mileage. Notice I said possibly. I'm being optimistic here, and the things I've read, better mileage is achievable. With the upgrades mentioned in previous posts the torque may peak at say 2,200-2,500 max, which would be in that sweet spot and I can drive right along with everyone else while the engine doesn't even break a sweat.
If I don't like the 292, I can rebuild my 283 or my current 350 and put one or the other in my other '65 for a different-driving truck. Or I can put the 292 in that other truck and put the v-8 back in this one. Either way I have options, and will be minimal out of pocket because I have the stuff already in my possession.
First things first, compression check. If that checks out, run the engine for 50-60 thousand miles and then rebuild it. If it doesn't check out, rebuild it or the head right away. Options. I like those
I'm actually excited to try this engine out, and the way the truck drives right now, it'll basically be about the same as the 350, just no huge secondaries to listen to when floored, and better power where I tend to keep the rpms.
