Quest for the best milage from a C-10

[lukecp]

Originally Posted by cruiserman

Buy a Corolla.

Yup...work the math out before you do anything. If you are doing this just to save money it may take 50 or even 100 thousand miles to get the payback you need, since building a new EFI engine is going to take thousands of dollars....you may be better off to just buy something else that will get better mileage that your truck ever could, and keep the truck as a toy.

[Ronin8451]

I have a '70 LT1 350 with a small solid lift RV cam, Holley Strip Dominator intake, a Holley SA770 carb leaned out by drilling air bleeds all backed by a 700R4 and 4.11 gears turning 28" tall tires in my '64 long bed step and it gets 19.2 MPG @ 70-75mph on a good day. I am right at the brink of pinging all the time and have to run a bottle of 104+ octane booster every 2 tanks ( I fill up at half tank to keep it mixed as long as possible). I bought the truck with the engine/tranny already installed and put the SA770 carb on it along with a new HEI ignition. I am playing with the ignition curves to help get rid of the pinging. I may try some 1.6:1 roller rockers to get a little more duration out of the cam to bleed off a little cylinder pressure. I also have headers with 2 1/4" exhaust and Flowmasters turned down in front of the axle. The high compression is a big factor in efficiency at the 2600RPM it turns @ 75MPH . I may swap the intake out for a Performer RPM to get more low to mid-range TQ. out of it .

Rick

Rick

[Ronin8451]

Originally Posted by cruiserman

Buy a Corolla.

I would rather drive an old gas guzzling Chevy than have to be seen in a little turd econo-box . Let the Fart-can kids have the "Crayolla" and drive your truck !
You would have to drive that ricer for 10 or more years to warrant the payback in better MPG , $20,000 for a new Toyota is a lot of gas money for an old truck .

Rick

[lukecp]

Originally Posted by Ronin8451

I would rather drive an old gas guzzling Chevy than have to be seen in a little turd econo-box . Let the Fart-can kids have the "Crayolla" and drive your truck !
You would have to drive that ricer for 10 or more years to warrant the payback in better MPG , $20,000 for a new Toyota is a lot of gas money for an old truck .

Rick

You can get a used econobox for around $2-$3k, and with a 5 speed get close to or even over 40 mpg on the highway (I've gotten a best of 43.5 mpg on the highway with my Saturn, going around 55 or so, it drops to 39 around 75 mph). Building a new EFI engine could easily cost $2k alone on a budget, and you might get 20 mpg.
I love my truck to, but my car paid for itself in gas money 2 years ago, and I've only had it for 3.5. Sure, my truck is 10x more fun, but it makes zero sense to drive it anywhere near as much as I drive my car (at least 15,000 miles a year, including a lot of long trips).

[mnunn454]

You were right, Brad. My bad

a quote from Mortec.com:

377 = 4.155" x 3.48" (5.7" or 6.00" rod) 400 block and a 350 crank with "spacer" main bearings.

I was also wrong about the article I read. It was called "The 350 Chevy should have built". It uses a 327 crank in a block bored to 4.155 (30 over 400 block). It's got a table top flat 400 foot pound torque curve from 2500 revs and up. Makes for some good reading that gives a little insight into the benefits of long rod ratios and some causes of detonation too. Here's a link to ithttp://www.purplesagetradingpost.com...%20engine.html

Am glad to learn also that Ohio Crankshaft can grind a blank to suit and eliminate any bearing spacers or extra thick bearings.

All, granted it's a "specialty engine" that most of us wouldn't run right out and build. But as long as diggertodd's doing research on what small engine combos yield great results, it's at least worth reading. Also, it's contrary to the usual theme of "no replacement for displacement". However, it is in line with diggertodd's smaller CID 305 build concept, only without the disadvantages of shrouded valves and sensitivity to detonation.

When it comes to fuel economy, a 350 SBC that uses cheap gas, has 11:1 compression ratio and yields 400 foot pounds of torque gets my attention (even if it does have Ford conrods in it).

Okay, 'Nuff of the sidebar. Back to the stroker MPG question at hand.

[49m]

I get 20mpg in my camaro that has a 305

[Morgsie]

Originally Posted by Buffalo Elk

Stick with the 350 idea....305's have notoriously bad bottom ends after 90k and you won't save any gas in the process.

This is odd considering the 350 HAS THE SAME BOTTOM END as the 305. Perhaps you are thinking of the soft cams that GM used from the mid 70s to the mid 80s. I also disagree with not saving any gas using the 305 compared to the 350.

[diggertodd]

Corolla - heh.... funny


Its worth every penny to drive a client to lunch or dinner in my C-10 and better yet - clear the throttle in the motel parking lot while all of the salesmen drones are climbing out of their taruss ... and Corollas. I'll shoot for 20 mpg and make my drives much more enjoyable...

Leaning towards a fresh 355 flat top, zero gap rings, .480 hydraulic roller cam and small runner, 76 cc chamber heads and dual plane intake and the EFI

for those that asked, you can see the TCI 4L60E contrller mounted on the passenger front wheel well

Since completed in August, I have driven her from central Illinois to Cleveland, Columbus, Memphis, Detroit and Indy twice... And won't quit driving the wheels off of her....no matter what the milage.

-----

and always remember... read Drag News

[67ChevyRedneck]

I don't think you ever answered my question? How sure are you that your speedometer/odometer is 100% correct?

[diggertodd]

As far as the actual speedo - it is one of the new Autometer electronic units that feeds from the pulses from the 4L60E sender, push a button drive exactly 2 miles (used a hand held GPS) and push the button again. Used the same GPS to set the TCI computer pulses per mile. No gear ratio - to tire diameter variables.

-Diggertodd

------

and always remember, read Drag News

[67ChevyRedneck]

That sounds cool!

Based on your RPM's I'd say your rear axle guess of 3.73 is probably right. Maybe try a set of 3.42's?

[jkade]

Why not put a GEN III motor in it??

[GlennBrittain]

I found the article on Sumner’s site while surfing for 87 Octane engine builds. I also found several more articles on so-called 87 octane high horse power engine builds. I went so far as to write to and email the publisher of the article” The 350 Chevy should have built” asking if the engine was ever installed and road tested. I did not receive a reply. I did find an article from another magazine following up on their version of the 87-octane engine build. This magazine did road test their version. They reported that the power curve was not suitable for a daily driver and they were ending their work on the design. I deleted my bookmarks after reading this article.
I now am looking for a more traditional engine that will give me decent mileage with an overdrive and 3.42 rear end.

[Cannon007]

go ahead and get some kind of fuel injection for it, get one of those retro full roller cam jobs, clean up the heads, or maybe just get some already done up aluminum heads that are matched to your cam and purpose, (talk with comp cams). the with that get to a dyno and dyno tune it, then with that you will know where your making good low reving power and then setup your rear end gearing for optimal gas mileage.

[Brad]

Originally Posted by GlennBrittain

I found the article on Sumner’s site while surfing for 87 Octane engine builds. I also found several more articles on so-called 87 octane high horse power engine builds. I went so far as to write to and email the publisher of the article” The 350 Chevy should have built” asking if the engine was ever installed and road tested. I did not receive a reply. I did find an article from another magazine following up on their version of the 87-octane engine build. This magazine did road test their version. They reported that the power curve was not suitable for a daily driver and they were ending their work on the design. I deleted my bookmarks after reading this article.
I now am looking for a more traditional engine that will give me decent mileage with an overdrive and 3.42 rear end.

GlennBritain, do you have any more info on this as to where I could read why it wasn't very good for a dd? I'm very curious about this 377 concept.

[GlennBrittain]

Originally Posted by Brad

GlennBritain, do you have any more info on this as to where I could read why it wasn't very good for a dd? I'm very curious about this 377 concept.

A few I found tonight

87 Octane Sites

http://www.compcams.com/information/Articles/
For the following two articles, states the original publication source
http://www.compcams.com/information/...HP0401-001.asp
Agent 87 on Comp Cams Site

http://www.compcams.com/information/...HP0201-001.asp
411 Horsepower on 87 Octane

AIRFLOW
http://www.airflowresearch.com/artic...le03/A3-P1.htm
The 350 Engine Chevrolet Should have Built

Summers Page
http://www.purplesagetradingpost.com...%20engine.html
The 350 Engine Chevrolet Should have Built

Hot Rod
http://hotrod.com/techarticles/engin...ild/index.html
DART 450CI Small Block (on 87 Octane)

Popular Hot Rodding-350 Bolt On Power Mods
http://www.popularhotrodding.com/eng...ons/index.html
This mag had another article on a high horsepower 350 on 87 octane but I could not find it again

MAS Performance 87 octane crate in this article
http://www.superchevy.com/technical/...mbo/index.html

Car Craft (this one is a ford 460, reading this will confirm why most of us choose Chevy’s)
http://www.carcraft.com/techarticles...460/index.html

[cruiserman]

Originally Posted by Ronin8451

I would rather drive an old gas guzzling Chevy than have to be seen in a little turd econo-box . Let the Fart-can kids have the "Crayolla" and drive your truck !
You would have to drive that ricer for 10 or more years to warrant the payback in better MPG , $20,000 for a new Toyota is a lot of gas money for an old truck .

Rick

Who said anything about a new one?

[Green Machine]

We built a roller cammed, swirlport headed 305, 20 mpg - details are in the link

http://67-72chevytrucks.com/vboard/s...d.php?t=262413