1st Thread, saying Hello and ?'s

[csdineley]

Hello

Been hanging around for a couple months now. I've been around old squarebody's most of my life. My parents brought me home from the hospital in my dad's brand new 79 k20 diesel. Then I learned to drive in his 82 lwb 305/700r4. And in high school I had a 79 G20 van with a 350 Q-jet/ th350. But for the last 15 or so years, I've been doing the sport car thing and then the kid hauling thing. At the end of last year I decided to get another truck. And after 4 months of searching for one that was as stock as possible. In January I found an 87 R20 350tbi/th400 4.10. One owner who just pasted a way and the truck had been sitting in his garage for the last 5 years. It only has 90k on it and is as far as I can tell is bone stock down to the original Gm floor mats.
So I've been going through it and tuning up everything since it had been sitting for a while. New plugs,wires,cap,rotor,oil,filter,trans oil and filter, fuel filter, 2x sending units, 2x fuel pumps,power steering pump and hoses,water pump, radiator,thermostat,both temp senders,belts and O2 sensor. And running every test I can think of compression, timing, voltages, etc,etc,etc. The truck was and still is running great, just thought after sitting so long it could use a good tune up.
Now for my questions. It's only getting 10mpg. Which seems a little low to me. I wasn't hoping for high numbers when I got it. But I thought it should at least get around 13-15mpg. I drive only on back roads doing a steady 55mph with no stops (unless I get stuck behind a school bus but that's rare). And have a round trip to work of 30 miles. This is the same kind of mileage my old van got. I thought the tbi should help mileage. In comparison my dad's 82 got 18mpg on his 120 round trip everyday for 10 years. So am I missing something,is there any thing else I should check? And does this mileage seem right to you guys?
And yes I know it's a 3/4 with a 3 speed and 4.10 gears, none of which helps my mpg's. Also should state tires are 245/75r16

Thanks
P.s Sorry for the long post

[csdineley]

Here's some pictures

[Bloodhound]

That is one nice find you have there.

[Pop's C-10]

Nice rig & i think you answer ya own question...th400...4.10 gears..

[motornut]

Hi good score
looks nice and clean

[csdineley]

Thanks guys, I've been quite happy with the truck so far. Maybe I've just been reading to many post on MPG. Maybe Ive just been reading to many post about MPG. Where others are claiming 15-18 with their 4x4 and crew cab dually's. I just would like my truck to perform as well as possible. While keep it as original as possible.
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[ringger14]

Welcome. Nice looking truck! My 350 with th350 and 3.73s got 12 mpg max. Def should get different gearing if your wanting more mpg. 8-12 mpg was my average depending on how I drove or if I had to haul something.

[pwradder]

10 mpg sounds right on. my 4x4 86 'burban with a 700r/350/373s and electric fan set up averages 12 mpg with 80% highway driving. i also had an 88 half ton 4x4 with a 350 tbi/700r and 342 gears that got 13 with the same kind of driving. still wouldnt trade it for an econo-box though!!

[csdineley]

Nope, I plan on keeping it for a while, my last car was a eco-friendly Mercedes diesel that got great mpg in the 30's but it was such a boring car. So if 10 is normal for my setup. Guess I'll have to live with it. Maybe I'll start researching swapping in a 4l80e / or a 700r4, down the road. Do the electric cooling fans, or a front air dam really help mpg or are the gains not enough to notice? And hence not worth the trouble.

[pwradder]

I was always under the impression that the air dams were installed to help with cooling and i've always removed them.I've never compared the same vehicle with mechanical and electric fans in terms of mpg, but i can say that mech. fans sap quite a bit of engine power so i would have to assume that there is a mpg increase becase the engine doesnt have to work as hard. nice truck btw!

[nekkidhillbilly]

there is about a 1 mpg increase with fans isnt much but its cheap to do plus adds hp too. od trans is the only thing that is going to give a huge mpg increase.

[csdineley]

If I could get an increase of 1 mpg from elec. fans and another 1 from a front dam. Which I've read somewhere Chevy put them on for fuel economy, but now I can't remember where I read it. Anyway that would be great.

[6772fan]

700R4 for mileage increase, doubt the front air dam would do much for mileage, but I personally like them, if for other reason than it should minimally help with cooling and they were original.
And WOW, nice truck you found there. I like it!