mpg

[84chvy]

hey guys i was just wondering what everyone got on mpgs. give me your setup and mpg. ex. motor/trans/rear end gears/tire size/tire type/engine mods.

[1979C20]

Rebuilt 350 with a hearty cam. SM465 trans, 4.10s, 33x12x16(285/75r16) BFG All Terrains. Last time I checked im getting 8-10, but that was when I had 31's. Id guess 12-13 now since I had a tune up and the bigger tires.

[84chvy]

thats not good.

[black85k10]

GM performance 350 with 330 hp th400 trans stock gears 31x10.50-15 general grabbers at2 tires. the last time i checked i was getting around 12 mpg

[mrboyy17]

86 4x4 scottsdale 3/4 ton 6.2diesel stock tires, and everything stock
18mpg

[zieg85]

1985 C10 305 TH350 2.73 P205/75/15  15.6 mpg
1985 C20 454 4 speed 3.21 gears LT235/85/16 load range E 15 mpg
1985 C30 350 TH400 4.56 gears LT265/70/17 load range E 12 mpg

All taken mixed Highway/rural and all trucks have over 100K on stock engines with stock quadrajets

[84chvy]

thank you for all the replies.

[1MCP7.3/87GMC]

Sad part is I should be getting better then what I get. 1975 Chevy 350 tbi stock out of an 87 gmc 700r4 trans 3:73s pushin 33" savero m/t half town half freeway 13.1mpg that's the best I've ever got. My 84 2wd with a 290hp crate 350 with true duel exhaust flow tech headers running a 600cfm Edelbrock 700r4 and I believe 2.08 rear gears got around 7-8mpg but when I pulled that motor and put it in my 62 impala with a 3 speed on the column and unknown rear gears gets around 17mpg with factory exhaust manifolds and a offenhouser intake and Holley 570cfm carb. Not to mention the impala tachs around 1200 more rpms at freeway speeds then my 84 did.

[str8bloc]

1986 lwb 305 700r4 2.73 peg leg. i get 13 mpg even with a leaky carb  and esc dist.

[ehjorten]

I get a little over 11 MPG in my '91 V3500 with the TBI454 and 4L80e with 4.10:1 rear gears on 35's with 8" of lift.  Now that was a mouthful!

[bluecrew]

yeah, I'm digging up old threads.

Tell me if I'm crazy, but I bought my 91 V3500 300 miles away from me, and the whole way back, mostly interstate (~70-75mph) I scored 20 mpg.  Small block 350, 4L80E, stock everything.  Checked the math three times, still came out to 20.  Sounds insane, right?

[fitz]

Bluecrew,i agree. 20 mpg's from your set up does sound insane.
Trust me, I don't question your math, just  keep in mind when people change gears and tires the odometer does not read accurately.

[jaredts]

I hate to say it, but there's no way you're getting 20.

[howlinwolf]

speedo is off possibly. i can only make a rough estimate of maybe ten. 350, quadrajet, 425 propane carb, 3.23 gears possibly, 4wd with stock tires, a heavy ass flat bed, and 80 gallon fuel tank on the back

[slammed79]

I get 14.5 or so mixed driving, 255/60/15 3.73 rear, sm465, fresh tune up and rebuilt qjet all on a 350. That factors in how heavy my foot feels on any given day too.