I picked up 3 mpg on my 2nd series 55 Chevy pickup when I changed out the cam and rear tires. I went from a 302H cam to a 278 and went from 265-60 BFG's to 235-70. This made such a huge difference in "driveability." I figure that replacing the worn out Holley 650 and a good tune should bring me about 2 mpg more. I'm currently running a 400ci motor and a built th350 ****** with a 3.73 gear, and turns about 3,000 rpm at 60mph. Heads have been ported and polished, and I'm running a 69 camaro 302 aluminum intake.
Since this is going so well I'll go ahead with another question - & remember, this is about making mileage on a tight budget. What are the pros & cons of building an early SBC vs. tuning on a running, take out, "roller motor/TBI/TPI" SBC? TIA, JH
depending on who you talk to. I've been torn like an old sweater on a build such as that 59 wagon Im looking at or similar to your car build. I've got a 92 caprice I bought for the drivetrain. running driving 305TBI, overdrive. I think it would be great "everyday" drivetrain. Easy starts, good mileage. I picked up the good running caprice for 600. I even got ac with the caprice so I could get an under dash ac unit and connect it this compressor. All about recycling!
with all the TPI and t*******s? or just the long block? If no tpi get a 500cfm edelbrock for that thing and run it.
It's complete. Supposedly came from a Camaro. Gotta make a list of donors for a 200R4 or 700R4 trans now... JH
buick lesabre from the 80s. when was the last time you saw someone drive the snot out of one of those?
On topic, I was wondering if anyone has run a 6 pack on a small block with 2GC's and progressive linkage. Performance and mileage? Could it be? I hate electronic stuff, it breaks and you are stuck. Cheers!
Hey David, the six pack runs on the one center carb then when you stuff your foot into it, the other two open. So for the most part ( depending on how you drive) you are only running the one carby.
Definately an overdrive and smaller motor, and a little tuning. The L03 crate motor (flat tappet cam, 9.2:1 compression, 305) I dropped into my old 57' Pontiac with a TH700r4 and 3.36 rear gears did a best of 28mpg on the highway. I changed the q-jet that was acting up bad to a 600 holley and it dropped to 25mpg but with no lean surge.
I had a 283 in my 36 Pickup. It weighed around 2750 lbs. Edelbrock Performer with a 600 CFM Edelbrock Carb, factory jetting, Mallory Unilite Distributor, Ram horn exhaust manifolds, Powerpack heads, stock valves and springs, small RV style cam. I had a turbo 350 with a 57 Chevy rear end, 3.36 ratio. 2357515's and the end result was 18 in town and 21 on the highway.
I bought a low mile 91 Cadillac Fleetwood for $1000 Pulled the 305TBI and 700R4 Sold $1200 of parts from it (lowrider guys love this model grill, headlights, and tail lights) Sent the rest to the crusher for another $200 Rich
you took the words right out of my mouth. my 235 truck motor has max torque at 3K rpm and that's about the max rpm too. if i push the motor i might eek 3500 rpm. another factor with regard to gas mileage is wind resistance. simply staying within your max engine torque range, (depending upon your drivetrain and aerodynamics) may not be the most efficient speed, especially when driving a boxy vehicle. i found this at another site.:
How does 30.2 mpg from a 383 sbc and Tremec 5 speed? Now the car only weighs 1790 lbs and 85 mph is all of 2000 rpms so I'm cheating a bit. This was my 1st long drive after replacing the Muncie with the Tremec. One difference, had a MB AMG pour it all on as he was p***ing me, so I jumped on it and was getting spanked till I pulled a gear (4th = direct) and caught back up, shifted just before 5000 rpms, which is 130 mph, then hit it again for just a few seconds more and got off of it to compression slow down to the speed limit. Took the pic during the slow down to show the tall gear ratio overall, because these fancy ***ed electronic speedometers do not peg, just sits steady at 120 as the tach keeps swinging.
Haven't had time to go look yet. I'm open to a 200R4 or 700R4. Gonna try to hit the junkyard next week. Gott find a list of donors first though. JH
I got spanked good a few months back oversimplifying about gearing, but I will say that I have had several very similar cars and the mileage was almost always directly related to the rear gears. I got better mileage with a 455 '71 Grand Prix SJ with 3.08 rear than with a 350 '70 Cutl*** with 3.7something gears in it, for example. In my experience lower RPMs at speed always helps. Always. Then everything else matters. Disclaimer: I'm ***uming a stock or near-stock motor, not something that will barely idle. And I do not want to hear about your car that gets better mileage in 4th gear than in 5th. I'm talking about over a dozen cars, all GM, all 1968-1973, all V-8 and all but one automatic. Buick, Olds, and Pontiac motors, 350, 400, and 455. Rear gear made a bigger difference than displacement, compression ratio (varied by year and model), and 2-barrel vs. 4-barrel. I DO have a light foot on the throttle around town, though, so I will concede that some goofballs might drive their mileage into the ground with a 3.08 or 2.73 year by constantly dipping their foot into the secondaries. I'm just relaying my own personal experience over several years of paying attention to these things.
Sounds interesting... rear gear and tire diameter, if you please. And / or details on the hop up you have in the engine. Gary
I have taken so much flak on another forum for trying to combine performance with good mpg. A couple guys are convinced that your ride can only be fast if it gets 3~5mpg, and these are T bucket guys, so their rides are under 2000 lbs. Just finished putting 1200 miles on the new 5 speed. 1st fill 24.6 mpg, part of this tank was spirited driving 2nd fill 30.2 mpg, all freeway cruising 70~80 mph, all below 1800 rpms 3rd fill 15.9 mpg, had to get my jollies off after all the conservative cruising final fill 28.4 mpg, all freeway cruising 70~80 mph, all below 1800 rpms
i believe that the best strategy regarding mpg is focus efforts on saving money on gas first---before messing with the car. I.e., gas rebate credit card---.15cents / 5% off pump price. Then mess with the car. But this is a complex discussion intended for a separate thread. However, just so i don't forget, and to confuse the issue further, i was thinking about this the other day: Use of spool on the street. i know this is probably not the best idea---have to be real careful when taking sharp turns. But, less overall weight and more importantly, less reciprocating weight. Your thoughts?
[/QUOTE] Use of spool on the street. i know this is probably not the best idea---have to be real careful when taking sharp turns. But, less overall weight and more importantly, less reciprocating weight. Your thoughts?[/QUOTE] Sorry, don't think much of that. What comes to mind is fast wearing tires, broken axles, screech ladened turns and more than likely not any measurable increase in fuel mileage. Don't mean to slam your suggestion, as it has merits on a dragstrip, but not on my T that is driven 8000 miles a year. Those M/T's are not cheap. With the new 383 stroker and going to a steel flywheel, plus the added weight of the new Tremec, I have lost 66 hp over the 355, and gained about 60 lbs. This has taken me out of the high 10's to 11.4 in the 1/4, but this ride gives 25+ mpg, has a tame idle and great street manners.
New automatics with OD and lock up torque converters do just fine. I still prefer to shift, so I use a 5 speed OD manual, but agree with you, the older autos **** the fuel.
See if you can find the Popular Hot Rodding issues that had the Project Econo-Performer 1970 Monte Carlo articles in them. Had a 350 that got mid 20's mpg and ran low 14's and that was in the late 70's early 80's.
283 (stock comp or slightly higher) with a 350 cam, edelbrock performer intake, quadrajet carb, 3 spd manual with o/d and a good electronic ignition set-up. i like to keep the rpms around 2000 rpms at freeway speed. my '64 panel truck gets about 18mpg (mixed city/hwy) with a 230 6cyl, 3 speed manual with o/d and 3.73 rear.....sbc should get better mpg because you don't need to push it hard to get on the freeway. also for long trips you might want to make a cover for the bed. ***edit*** i just read you want to use a a/t only. then i would go for a 200r
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