Labor Day Putting down your wrenches or time for
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| | | | Joined: Dec 2011 Posts: 264 Shop Shark | | Shop Shark Joined: Dec 2011 Posts: 264 | Finally got the chance to check my mileage yesterday since installing my 5 speed. With a 261 and a zenith carb on a 86 mile drive. A little town and a little highway I came up with 19.93 mile per gal. | | | | | Joined: Dec 2015 Posts: 2,062 Big Bolt Forum Moderator | | Big Bolt Forum Moderator Joined: Dec 2015 Posts: 2,062 | That's great! I'd be happy with half that in my 2-ton! I took it out this last weekend, almost all freeway, 6 mpg. 327 and SM420, but going down the freeway it is spinning 3500-4000 depending on if I keep around 60 or push a bit to keep up with traffic closer to 70! | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | I got 6-9 mpg with my 503 in a 630 for about 600 miles, with a 6.5 rear end ratio.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Jan 2015 Posts: 914 'Bolter | | 'Bolter Joined: Jan 2015 Posts: 914 | Finally got the chance to check my mileage yesterday since installing my 5 speed. With a 261 and a zenith carb on a 86 mile drive. A little town and a little highway I came up with 19.93 mile per gal. Down hill both ways?  Jefffrey
Last edited by 32vld; 06/28/2016 2:54 AM.
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | congratulations, basham
What mode Zenith carburetor? | | | | | Joined: Dec 2011 Posts: 264 Shop Shark | | Shop Shark Joined: Dec 2011 Posts: 264 | If memory is correct it's a 11965 | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | 11965 was used on 1957-1961 270 GMC engines.
That would be a nice match for a 261.
| | | | | Joined: Mar 2003 Posts: 1,132 Shop Shark | | Shop Shark Joined: Mar 2003 Posts: 1,132 | Wish I could get that MPG with my 283. Mine is closer to 11/12. I have the tendency to reduce gas mileage claims by 25 per cent to get realistic. Just sayin.
Weeds | | | | | Joined: Aug 2006 Posts: 486 'Bolter | | 'Bolter Joined: Aug 2006 Posts: 486 | What model truck is that in? Seems to be a good combo.
'64 swb stepside (gone)
'57 1 ton
'53 phone truck
'59 swb
'46 1 1/2 ton
'68 swb gmc
| | | | | Joined: Dec 2011 Posts: 264 Shop Shark | | Shop Shark Joined: Dec 2011 Posts: 264 | 1953 half ton with 390 rear end
| | | | | Joined: Dec 2015 Posts: 2,062 Big Bolt Forum Moderator | | Big Bolt Forum Moderator Joined: Dec 2015 Posts: 2,062 | Wish I could get that MPG with my 283. Mine is closer to 11/12. I have the tendency to reduce gas mileage claims by 25 per cent to get realistic. Just sayin.
Weeds WAIT, Don't take 25% away from my 6 mpg... I'll hardly be able to get up to freeway speeds before I need to stop for gas! LOL... On a side note, I bumped my iming up 2 degrees and kept the speed down (mixed in some mom-freeway driving) and got 8 mpg on the last tank. Anyone know how much engine temp affects gas mileage? My engine does not have a thermostat (or it is stuck open) I need to pull it apart and put one on when I replace all the hoses. | | |
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