Looking for better fuel milage

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I get what all you guys are saying.....but the absolute most/best you are gonna squeeze out of it with ZERO playtime on the highway for the entire trip is MAYBE 14...MAYBE and that is still pretty shitty mileage for a cross country tour with fuel at $4 PLUS per gallon.

IF it was built to Lobe & thump and sound hot then it prolly is not running at peak efficency, hence really crappy milage...Just sayin not flamin......

my suggestion is just take the tour ( if you have the $$) and forget about the cost....it may be the last one anyone does for a while
 
Just pull 2 plugs out, block those 2 cylinders int ports at the gasket, tighten those 2 exh valves so they hang open.

now you have a 6 cylinder with that mean idle your wife likes.
 
805moparkid said:
really weird cuz on my built /6 (10:1/246 @ .050 cam/600DP with 66 primary jets) i got 20mpg with 3.91's @ 3500 rpm to vegas and back...

sounds you got something not working right... check all your brakes for drag parking brake cable to tight?
Click to expand...

my 340 241@.050 3.73 gets 15-17mph HWY going 340mile trip to fresno, no vac advance either.
Pobably gets 10-12 around town not stomping it.
 
17 mpg out of a 72 340 w 355 gears is an bit of puffery...I had that same set up went up to 3.91 and back to 3.55 850 thermoquad and dynotuned at HUB's ( famous tune place back in the day)...never ever saw 17....maybe if you idle around and turn it off on down slopes ...beyond that somewhere in the 10 - 12 range..... so I would be interested to see your dyno specs... you may be running dangerously lean
 
I understand what you're saying, but some of us can tune...I for one.
I jet down the primary till the thing surges a lil at cruise, then go up 2 jet sizes.

I run intial timing @ 24-26* at idle and have the advance limited to get 32-34*
I run a capacitive discharge ignition and a hot coil and I drive in the cam range, never under it, unless Im idling.

My motor has very low miles since I just freshened it in '09 with lighter pistons.
 
1wild&crazyguy said:
I understand what you're saying, but some of us can tune...I for one.
I jet down the primary till the thing surges a lil at cruise, then go up 2 jet sizes.

I run intial timing @ 24-26* at idle and have the advance limited to get 32-34*
I run a capacitive discharge ignition and a hot coil and I drive in the cam range, never under it, unless Im idling.

My motor has very low miles since I just freshened it in '09 with lighter pistons.
Click to expand...

this is what most people miss... if your in the cam range (peak torque) then you will get your best mileage... to high or low and either the overlap is letting fuel out the pipe or your just in it to far...
 
StrokerScamp said:
... Something on the order of 218* intake and 230* exhaust with a 112 lobe separation maybe even 114 to keep the torque curve very wide. Would probably start about 1500 and not quit pullin until he got tired of it. Would pull over 6K. A milder cam, with 3.23 gears and a stock converter would BE faster than what is there now.....because it would rev quicker, have much more bottom end torque and be much less peaky in terms of the torque curve. The cylinder pressure with a milder camshaft would skyrocket resulting in much more power...
Click to expand...

Been there, done that, absolutely true.
 
Info only: I gained 17% increase in gas mileage going the Projection route. That's ~20 mpg highway, 17 mixed. Another 2 mpg plus added performance when I swap back to 273 heads, but I take a real hit in >4800 rpm range.

Rough estimate of 2 year payback at today $4 + per gal pricing and 10K miles per year.

This is a 65 Bcuda, 318 +30, CDI, 2bbl TBI, Edelbrock Performer, CompCam 268, 4sp, 3.23 SG, 205/70/14. rwh
 
I've got it up to 11 mpg in town driving. Haven't had a chance to really do
much Interstate driving for long distances. Come next Tuesday that will
change. I-65 to Georgia and then on to Flordia.

I did end up changing the springs in the dizzy to the 2 light weight units.
Total timing (35 degrees) is in at around 1700 r.p.m. The engine seems to like that
the best. Welded some bungs on the down pipes and installed an 02
sensor. Air/fuel was 13.5 at cruise and 10 at wot. Could have leaned it
out a bit at cruise but I left it as it was. I had rather not have any
detonation issues by leaning it out too much.

I'm getting the rockers adjusted tomorrow and getting the headliner
tightened up on Friday. I'll never install another one of those again.

I'll have Strokerscamp update you on the highway mileage after I
stop and see him on the way down to Flordia as I won't have any
computer access.
 
Met Tony and his wife today. Had lunch with them. Fine folks. Even got to drive the little black car. What a beautiful ride! None of these pictures here do it justice. A bit peppier than you might imagine, too. Tony says so far he's gettin 12 or so MPG, which ain't too bad considering the 3.55 gear and the relatively loose converter. The car runs really nicely. Had a great time Tony. I'm the big ugly one in the FABO shirt.
 

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What size rear tires Tony? That does sound like low idle vacuum to me but I have not measured what my 340 has with a very wild cam to reference from. The light weight of these cars should give good milage unless a lot of unburned fuel is going out the tailpipes. My hotrod burns a lot of gas with that lumpy camand my heavy foot. Holley 850 DP carb with an aircleaner like yours.
 
I get 18 mpg hwy in my Newport w/ 383. A light Dart should do much better. I added the Holley Pro-jection 2D in 1996 but no noticeable improvement over the 2 BBL carb. I agree that your main problem is cam, intake, converter all for racing.

A fairly inexpensive upgrade is to add an O2 sensor to the exhaust. Without it, hard to say what your carb is doing. Holley has a little 3 LED monitor box. List for $120, but I got much cheaper on ebay. Before I found that I was using a 1 LED box from a natural gas system I got on ebay w/ O2 sensor for ~$10. w/ dual exhaust double everything or just monitor one pipe. That will set you up for later EFI systems like Pro-jection, MegaSquirt, FAST, etc.
 
I am ceertain that Tony could do all kinds of things to make the car faster and more efficient. After seeing it hearing it and driving it though, it's pretty cool like it is. Sorta old school bigger is better kinda thing. It's a really cool ride.
 
I didn't think any body was as big and ugly as I am LOL. Nice to put a face to the voice there Stroker.
 
I've wondered the same thing, I saw a couple of posts elsewhere, so I know he's still kickin'. Maybe I'll call him.
 
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