Mileage report from trip, decent.

[jku72]

Just got back to work from Maine. I drove my 1968 Chevy C10 suburban 263 miles, and used 14.4 gallons. It took a whisker under 5 hours, so while my highway speeds were 65 to 70, my average speed (including toll booths, construction, etc, was fifty-somthing miles per hour.
By my math, that is 18.2 mpg. I have a 350 with a q-jet, sm465 4 speed, and 3.08 rear gears, and 31" tires on the rear, 29" tires on the front. Tire pressure in the rear tires was 50 psi, front 40.
I have a fairly high compression ratio, and that is key to good mileage, as is a healthy HEI, and synthetic oil.
By comparison, my 2002 F**d f250 (with a bad transmission btw), with a powerstroke diesel, gets between 17 and 19 mpg.
35 years, zero progress.

[68 Suburban]

That is great! See, these beast can get good mileage!

[tom hand]

What kind of tires are you using to run pressures like that????

[jku72]

In the rear, BFG 31 10.5 15 AT. 65 psi is max pressure BTW, according to BF Goodrich.
In the front, I have Hoosier 255/70/15's. They are a real nice high perf. tire. Helps handling a great deal.

[68 Suburban]

What type of compression are you running? Also, what cam do you have?

[jku72]

Compression ratio is a not a certainty, but Based on compression pressure, and a few other factors, my own S.W.A.G. would put it around 10.5. It has heads that are off a 1969 camaro, but I dont have too much data. The cam has got to be stock. It idles quite well. It does have a Performer intake, but is also hampered by a puny single exhaust, I think its a 1 7/8ths inch thing. Thats why mileage over 70 drops off a cliff. @ 75 to 80, I'm getting 12-13 mpg, I think backpressure just gets so high it chokes the engine up.
Another factor that is not thought of, and may not even be a factor, is drum brakes all around. Disc brakes stop way better, but are a constant drag(albeit slight) Drums have springs that retract and offer less drag.
I have an ACCEL super coil, and 8mm plug wires, and the plugs are currently gapped at .055, and that has been a great combo as well. I advance the timing till it just pings under acceleration. For around the house driving, i back it off a couple degrees, for long trips like this, I do as much advance as I can safely get away with.

[old Rusty C10]

of course the bad transmission in the Ford has nothing to do with the lack of fuel efficinecy

[jku72]

The 02 F**d got that17-19) before the trans went. Thats what they get. In reality, its not that bad for a 7400 lb truck, but i expect more progress in 35 years. My burb cost 2 payments of the 02.

[68 Suburban]

do you run synthetic gear lube?

[jku72]

I bought enough Mobil 1 full syn. for the trans and the diff, but i havent had the time to change to synthetic gear yet. Next time I get a day off maybe.
This truck really does not have a lot of tricks at all. High compression, a hot ignition, and the right gearing is all. I paid $750 dollars for it(the whole truck), plus the cost of the rear gears(used, traded the 3.73's), $50, plus the cost of new wheels and tires, $400, plus a power brake booster(used), $25, plus a power steering box and pump(used), $80. Oh yes, the HEI, plug wires, and plugs were another $150, more or less.
I bought, then added the above, in Portland Oregon 2 years ago. I bought the used parts off a guy in Washington State, just across the border from Portland, I wish i remembered the fellows name, he is likely a board member, but that was long before i ever heard of this board. He was a fairly small time parts supplier for 67-72 chev trucks. He had a souped up C5 blazer.

[dons72]

jku72,
Wher is cornville at in Maine? I lived outside of Ellsworth in a little town called Franklin for nearly seven years before moving here a year ago. Hope to retire the in a few years, but dread the tourist season traffic.
Don

[jku72]

Right next to Skowhegan.

[Brad]

jku, I bet you're thinking of DC Truckparts. The guy's name is Dave. I bought a real nice lwb bed from him a couple years ago. Located in Vancouver.

[jku72]

Sounds about right, is Dave a member here?

[Brad]

I dunno. Seems like everyone I talk to about these trucks isn't on the web! They don't know what they're missing!

Btw, have you ever been to Nova Scotia? I've always wanted to go there! Do you have any pics? Good websites?

[jku72]

Yeah, I've been to NS a few times. There are some really really cool fossils on the beach in Joggins Bay. The ocean is slowly washing away the beach cliffs, and it just happens that 60,000,000 years ago there was a tropical jungle there. There is a whole fossil forrest being washed into the ocean. Ever wanted to see primordial tree trunks? They are there. We are talking pre-dinosaur stuff here.
Elsewhere, NS is very beautiful, and, due to the new high speed ferry, only a few hours away, with a car. It is similar to the US in most places, but with, in a lot of areas, less people.

I have been haggling with my wife to get my pics ona web site, but she is just way too focused on being a Mom. She has her priorities all wrong! Sometimes I'll get some pics up. I have them, just gotta do a little legwork.

[Brad]

Hey, I'd love to see them! Email me when you get them up, wouldya!

[jku72]

I just did the return trip to Maine. I filled up at the same two gas stations, drove the exact same 263 miles, and, Oddly, I used the same 14.4 gallons on the return trip. I myself would be skeptical, to use exactly the same amount of gas both ways, well, oh well. I did. I am sure if I remembered out to the hundreths place it would be different.
Either way, I can pretty well confirm 18.2 mpg.

[1972ChevyGuy]

geez, i use up 3 gallons on a 1/4 mile pass