what kind of gas milage do you guys and gals get with "built" motors ?? I just got finished building a motor for my 72 chevy and i was wanting to hear from some of yall about gass milage.
my old chevelle got about 19mpg freeway and about 13 or so city. but i was into it at every light. edelbrock 600 carb torker 2 intake trw cam stock 1976 heads and bottom end with a 2:73 and a th400 and 255/60/r15 but the car wasnt fast so maybe u mean more built
It's got alot to do with the gearing, too. If you had 3.45's you'd be pleased with the in city performance but you'd be down to 15 mpg on the highway.
I never got very good gas milage from any built motor I ever had. Four barrel carbs don't get good gas milage when all 4 are usually mostly wide open. I suspect there was a posibality they COULD have gotten decent milage if you don't get carried away with the gears. But I wouldn't know. Gene
I love this question. It only beggs another question. > Who in the hell would even worry about Gas Milage if you want to run a built motor? People who worry about their gas milage are who they build Toyota Echos' for.
interesting post, the motor I built is .60 over, lunati 292 duration cam, edelbrock daul plane intake, holley 670 street avenger carb and hooker headers. I'm only 16 so gas money is hard to get
.60 Pistons = $250? Cam kit $ 200? Manifold= $ 200? Holly Carb= $400? Shift kit= $50? Headers= $200? If gas money is hard to come by, Why would you spend this kind of money and worry about what $2 worth of gas will get you? Your $2 would buy you more if you hadn't "built" that motor! I guess what I'm trying to say is you have to chose One or the Other.
IF you stay out of the secondaries most of the time, and you run manifold vacuum vacuum advance on your distributor, you can probably get around 16 mpg. If every intersection light is a pretend drag strip "christmas tree" you'll get maybe 6 mpg.
anyone know where or who had the very informative post on building an SBC that put out very good #s and good mpg?
I rebuilt the engine in my T-bird summer before last, it's bored .060 over to 301 cu in, Holman & Moody 882 cam, with 304 duration, 238@50 and 506 lift, ported heads, lightweight valvetrain, a factory '57 2-4 intake with Holley 4000's, Mallory Unilite ignition, MSD6AL box and MSD coil. The tranny is a T-5 with .63 overdrive 5th gear, the rearend is a Dana 44 with 3.31:1 gears and tires are 27" tall Goodyears. I did the long haul on the Power Tour last summer and I was getting 18.9 mpg on the highway while running 70-75 mph. I'm sure the tall gearing, tall tires and the overdrive was the biggest help. My gas mileage was terrible in town, I'm running straight linkage, not progressive, and I love the sound of the engine with all 8 barrels opening while I was running it thru the gears. I know that I would be alot better off with a single 4bbl carb and a street friendly cam, but I love the way it looks and I'll put up with the in town mileage
Ford 302, unknown fairly lumpy cam, long tube headers, MSD ignition, Eldy performer carb (600cfm). Trans is C4, 2000rpm stall, rear is 8" with 4.11 gears. I'm getting about 12mpg. Around here, most roads are 50-60mph to work, I guess that counts as interstate speeds. I had a 79 chevy with a mild 350/350, eldy 650 carb, 2.43 rear... it did pretty well, i'd guess 18-20mpg average, until I got in the secondaries... then, it was pretty close to 6-10mpg. Me and a buddy would play around on back roads, it would go through a quarter tank like it was pouring it on the ground. This 302 doesn't... I can baby it, or floor it, it doesn't make a lot of difference. For what it's worth, i'm getting better gas milage from the 91 premium gas than I was with the cheap shit.
Thi first engine in my roadster was a 350 chevy, 4 bolt main, steel crank, forged 12to1 pistons, Huge solid lifter cam, early 60's "Fuelie" heads and topped of with two carter 500 carbs on an edelbrock intake, oh and a MSD ignition. headers of course. I was running a 3.55 read end and was lucky to get 9 mpg. I also had to run sunoco 94 or better or it would spark knock bad. The fun factor greatly outweighed the poor mileage
I had a 400 hp 350 S-10 Blazer. It didn't so much get mileage. It got about 14 ypg....yards per gallon. Besides, who cares about mileage anyways with gas so cheap?
my 289 gets about 11 around town, less than that when i am usin' the stoplights like a "christmas tree." i drove down to portland with it and was pretty easy on the throttle. I think i got 18 MPG. 500 CFM carb, 270 duration int/exh and .500" lift on both sides and 2.72 gear in the rear. Upgrading to T5 and 4.11s, it will be fun...and my highway economy won't get any better, maybe a little because it is a manual, but it will work out to about the same final ratio i currently have in the car.
My '34 coupe with the 351W C4 and 3:50 gears gets about 18 on the highway and 12 around town. The 351 is a crate motor with a hotter cam and 750 Holley.Pushing about 410 hp.
My 62 chevy II (3000lbs with me in it, th400, 4000rpm stall, 9"rear w/4.11's, 30x13.5 [DOT]slicks, 1 3/4" equal length headers, 3" duals with x pipe, MSD Pro Billet dizzy with 6AL and Blaster HVC coil)) USED to get about 12.5 mpg pretty much all around as long as I kept my foot out of it most of the time. That was with the "HOT" motor: 406 SBC, 11.6:1, 6" rods, 268/270@.050 - .632/.632 solid roller, CNC ported Brodix Track 1's, fully ported edelbrock Super Victor intake, 825 Race Demon carb...(ran on sunoco 94) After a main bearing decided to leave the building , I put in a motor that I built back in high school. With this motor, it only gets about 9mpg: 406 SBC, 9.5:1, 5.7" rods, Comp 292 Magnum, GM 487 X castings, fully ported by me (in high school) but still 1.94/1.50's, box stock Edelbrock Victor Jr, Holley 750 double pumper... (Also runs on Sunoco 94) So as you can see, the MORE "built" motor actually got better milage (and performance) than the LESS "built" motor... A lot of that comes down to volumetric efficiency and proper matching of parts. SCOTCH is the guy that needs to come in here and tell us all what's up!
So much has to due with efficency. My SBF has high compression 10:1 runs .610 lift intake with dual quads and high performance cast iron heads roller rockers and lifters and gets good milage when my foot is not in it. On the highway to Louisville last year I averaged 19/20 mpg, but , I was running 3.05 : 1 gears in the quickchange in a fenderless model A coupe. Never checked it around town with the 3.78 :1 use. I think a high performance motor not laboring can get good fuel economy but not in the same range as a 4 cly.
With the Hellcamino, I could get 16mpg if I was very careful with the fun pedal. At the time, it was a 10 to 1 SBC (355) with good flowing aluminum heads and a .560 lift Lunati Hyd roller cam. The worst part of the mix is a 750 Barry Grant Race Demon. It has a TH400 with 3500 Coan stall sending power to a 9" with 3.73 gears. I had pretty short (26") rear tires, so on the highway, I'd turn about 3200 rpms @ 70 mph. It would run 12.70 @ 104 in the quarter mile. On spray it went 11.08 @ 124. If I had an overdrive tranny and numerically lower gears, I'm sure I could get over 20 mpg on it. I'd like to see what Scotch has to say on this topic...
best MPG i got with a built up motor was a 71 307 chev with a 300HP 327 cam aluminum intake holley 600 305 HO heads & dauls car got like 22mpg on highway & 16 round town & had a lot of guts off line that went to bout 110 then peaked now 427/500HP in a 68 SS velle with 556 gears got less then 8mpg no matter how it was driven & took airplane fule
Actually the most fuel-efficient vehicle i mown right now is my bucket. The dual carb beast with a 5-speed gets about 18 round town and 25 on the freeway!
You can "build" a high performance motor to get good fuel mileage if you build for torque, not high end HP like a drag motor. I have been going through this same issue with my 16 y/o son about our dodge project. This is why we chose to go Mopar and not SBC. I'm not bashing Chevys; I've owned several with built SBC, LT1 and LS1 motors, but the big valves and ports that make the sbc breathe better than stock fords and Mopars are the ENEMY when it comes to low speed throttle response and hence mileage. Our motor is based on a 318 that i bought with 999 trans, steering collumn, and all of the wiring harness out of an 85 Dodge diplomat. It was rebuilt with 40k miles since. I paid $250 for all of it, complete with A/C, PS and all the attachments and linkages (shift and kickdown) included. Stock its rated at 120 HP (woof, woof) and 245 ft lbs torque. I bought off ebay the following necessary parts used in great condition: Holley 600 cfm elec choke single pumper, vac secondaries $100; Edelbrock Performer (NOT RPM, Torker , etc) intake $80; new Melling truck cam and lifters, 204 intake and 214 exhaust at 050, total lift at cam .455, which is exactly what these mopars need with the stock small port heads, $70. So far, I'm into $500 total for a motor that will put out an estimate of 225Hp and 285 or more Ftlbs of torque once I get the shorty headers worked out. I'm thinking its worth it to spend the bucks on Edelbrock late model Dodge ram shorties with ceramic coating even though its a budget buster at $330 from Jegs. I expect 20 MPG or better cruise with the 3.08 rear gears without overdrive and still enough grunt on the street to not embarass us. I don't expect to beat any 4.6 Mustangs or LS1 F bodies but we'll be way cooler than them in the process.
When I first got my 327 in my wagon running it got 13 on the freeway when I drove it across country. Now that it is broke in and tuned better, I get 18.. oh ya, I run 253 rear gears.. its a great freeway car, slug off the line
a buddy of mine runs a 460 with crank monted fuel injected blower dont know how built it is but he runs 10.01 in the 1/4 when it was on carb it ran 8-10 mph on the motorway at 70ish hes now gettin 25mph he loves it
First, to everyone that said "who cares about mileage?": I DO! I hopped up my first engine myself because I couldn't afford to have someone do it for me, and because I couldn't afford to buy a "fast" car. Isn't that like everyone here? Money has always been tight for me, but I've always been able to come up with the parts I need to make my car more powerful. And I've justified it with the idea that more power comes from more efficiency. This is very true with 50's and earlier engines(at the time that was what I could afford) Bump up the compression, make it breathe better, and you'll get more power and better mileage-- Which can result in savings overall. Second, for those wondering about my numbers: My 54 Belvedere with flathead 6, 3/4 race cam, three side-draft Mikuni carbs, tube headers, 3.73 rear with OD, can get 22 on the highway My 70 Buick stock built 350, Q-jet, 3.00? gears has gotten near 20 My 55 Belvedere flathead 6 with 2 carb intake, dual exhaust, dual point ignition, drove 500 miles to a drag race, raced all weekend, drove back, and got better than 17 for the entire trip. I'll let you know what it does now that it is built about the same as my 54. That's all I've got to say about that
Gas mileage? I get shit mileage...but damn I look cool doing burnouts. If I could put up a twenty foot mirror and do burnouts in front of it all day I would. mmm mmm burnt rubber
355 SBC, 11:1 pistons (about 10.5:1 with the 72cc heads). Heads built with big valves,full roller rockers, Comp 270 "magnum" cam, Lakes style headers, MSD ready-to-run H.E.I. type dist. with vacuum advance, edelbrock dual four intake with edelbrock "performer" 500 cfm carbs, progressive linkage, Muncie M-20 4-speed, 3.40 8 inch rear, 31 inch tall tires. Both carbs are jetted 2 stages leaner on primary and secondarys using the edelbrock carb manual. I get 20 on a long interstate run. I am estimating 15-16 normal driving in the suburbs. The tach is reading about 2400 rpm at 70 mph. The car is an all steel "A" coupe with no running boards and bobbed fenders.
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