18.2 MPG first short trip - No tuning yet !!!

[Green Machine]

First short trip in the newly road worthy but not yet finished Green Machine gave us 18.2 mpg. Went 225 miles, some city driving. Motor has about 500 miles on it now. All that we did to tune it was set the timing on the boneyard HEI, put on stock jetted edelbrock 1406. We plan on working on the advance curves and will try to tweak the carb. Planning on adding headers this next spring, tuning and headers might make it better, want to try to get 20 mpg, but maybe I shouldn't mess with it !!

(don't tell anyone it is a lowly 305)

[Aarons72s]

Man that is awesome. I would like to here complete specks, tranny, axle ratio, tires. And some pics.
Aaron

[Jerry Jones]

Nice

[QKENUF4U]

dont complain, your lowly 305 gets twice what my bb gets.

[7387chevys]

When I put headers on my 305(ho camaro engine 1406 carb ported heads inch carbspacer performer eps manifold) got me 3-4 mpg.1985 chevy 3.08 gears 700r4 trans 4x4
Shane

[tkeduk8r]

Awesome gentlemen... nice to hear... 305 isnt too bad after all is it?!... GO FOR 20!!! I tweaked and tweaked and ill i was able to get was 19.2 on that return trip from shawns last May.. But I do have headers, my 305 is unknown rebuild specs and I have those 31 inch long trail t/a's, so i figure what i gain with headers, i lose with the tires... and i have a stock intake and quadJ... how do you like that 4 speed now that youvce had a chance to run it??? I need to live vicariously off of other peoples storys wiht being back in school n stuff ... let us know.. and PICS TOO!!! wanna see her again...
--Mike

[Green Machine]

Here's what we are running, 1970 C10, 3.73 posi, A833/NP440 4 speed overdrive (.73) manual trans. 31 inch tires, P265/70/R17, 1989 Camaro 305 TBI engine, stock swirl port heads, Edelbrock performer 2104, Edelbrock 1406, stock roller cam, rams horn manifolds and dual exhaust with restrictive mufflers. Engine had about 140k on the clock when we got it, we just put in rings and bearings, t-chain, oil pump, new valve seals but no valve job.

60 mph is about 1700 rpm on the tach, just motors right down the road, loafing along. It really does have pretty darn good power too, more than I was expecting, pulls good up to 5000 rpm. The HEI is from a boneyard, we have had that all apart, cleaned and lubed up, the mech and vac advance both work, but it will need tuned to this engine. Tuning the dizzy, experiment with the carb calibration and adding headers and decent exhaust might help. Since it seems pretty close, we might not mess with the carb right now, because when we add headers, the carb likely would need different calibration. Lookin good so far.

[SB406]

Awesome. I think you can reach 20MPG with that 305. My TBI 406 hit 20.9 with a 700R4 (.7 OD)/ 3.42 gears, No headers. That manual tranny helps too.

[7387chevys]

Originally Posted by SB406

Awesome. I think you can reach 20MPG with that 305. My TBI 406 hit 20.9 with a 700R4 (.7 OD)/ 3.42 gears, No headers. That manual tranny helps too.

Please give us the specs on engine ............heads.......intake......compression ratio........camshaft............any other little fuel sipping secrets.........hows the power?
Shane

[beaterC10]

Originally Posted by Green Machine

60 mph is about 1700 rpm on the tach, just motors right down the road, loafing along. It really does have pretty darn good power too, more than I was expecting, pulls good up to 5000 rpm.

How does this work out for passing, hills, or other instances when you need more from the engine? I was looking at the same trans and a similar rpm range from my 350 in a 2wd 1/2 ton. I was wondering if that was too low of an rpm range for the engine. Are you using the stock Hurst shifter on this trans?

[70rs/ss]

I have a 350 vortec in my cop spec tahoe with a 3:08 gear and 4l60e and get 17 ish. I wouldn't give up my big stick for a 305, but if you just drive it more power to you. I can down shift into second at near any speed and get out of my own way, not sure the wee oh five can do that. As it says in the siggy it is cop spec so it'll evey bit of the posted speed on the speedo and cruise at 90 mph and about 2-2500rpm, talk about cruizin'.

[Paul72]

tell me about "rapid city next spring" is it a meet? is there a link about it i can read?

I think this is what they are talking about:

http://67-72chevytrucks.com/vboard/s...d.php?t=215266

[Green Machine]

Originally Posted by beaterC10

How does this work out for passing, hills, or other instances when you need more from the engine? I was looking at the same trans and a similar rpm range from my 350 in a 2wd 1/2 ton. I was wondering if that was too low of an rpm range for the engine. Are you using the stock Hurst shifter on this trans?

Moderate hills seem to be no problem, it will handle 4th from about 40 mph (1200 rpm) on up. Sometimes happiness is a stock cam and a small one at that (179/195 @.050 on a 109 LC. As far as passing, 3rd seems like a nice passing gear, and you could run all day in 3rd if needed, thats about 2300 rpm @ 60. If you really want to get with the program, drop down into 2nd, that will pull up to 75 mph @5000. 100 mph is about 4000 in third, still pulling when I chickened out !!! Yep, stock hurst shifter.

[ND_guy]

Im jealous of your mileage with 4.56 and a four speed I only pull down half that.
also what kind of wheels are those they are very sharp against that Dark green

[Billla]

Originally Posted by Green Machine

4 speed overdrive

Very cool and a beautiful truck - but that's cheatin' '-)

[67ChevyRedneck]

I had an 86 Camaro with a 305 (Q-jet) and 700R4. I got about 16 city with it and it would get 21 highway. 18 seems reasonable for a truck.

[68C15]

so this means you will be taking ol' green to Rapid City next spring?





(bring an extra OD for me stepside)

[Green Machine]

Sure - why not - I think my sons are planning on it already !!!

[SOON2BLAZE]

hows that trans shifting?

[Boise69]

tell me about "rapid city next spring" is it a meet? is there a link about it i can read?

[Green Machine]

I need to get my good camera fixed, so it will show up better, but those are the Cragar Soft 8 chrome steel wheels, they are 17x8 4.5 bs. Always wonder when you order wheels if they are the right thing, I think they look sharp too. I do have to get better pictures on here, the chrome in the wheels brings out the metallic in the paint.

[Bad71chev406sbc]

Hey, I liked my 305, it was a hot little motor. regularly got 16mpg with my lead foot and a 4barrel and 4spd. Came out of a Impala 9c1.

[70rs/ss]

I had a 94 9C1 with the Lt1 and pulled 22+ MPG and I was going 80-85 mph everywhere I went. The PD cars are high gear ratio and OD trannies, that why you can't outrun them. You may be faster down low, but my tahoe'll go 90 mph and 2000-2500rpm all day, so sooner or later the runner blows up and the copper catches you!! If you can handle leaving like a dog, then 3.08 and OD'll bump the MPG way up if you do extended driving (not stop and go traffic driving)