Fuel Mileage?

Thikstik wrote: So if your running an 800 it'd even be a tiny bit crisper with a 750.  Re ultimate cfm usage, i hear ya.  I wonder how much your 6 is pulling open the air flaps.     Re adapting a qjet to clif intake, i pulled my carb and adaptor to mock things up as i found a Mr Gasket qjet to holley adaptor laying around.    I used a qjet gasket to mock a qjet base and it wasnt pretty...the air flow from the qjet would have to sit oblong over the 4 holes and it looks to be a strong flow killer.  Actually  it would create some terrible turbulence. But, i think the cliff adaptor could be traced out and opened up to meet the bigger qjet pattern and work.  I should upload a pic.  The stack up of 2 spacers may be a foul ball also...dont know.  It actually could help tork.  Shaggimo, have you seen how bizarre the air flow has to be going from the qjet into the 4 bores?   I know that the Offy has the 4 bores cast into many.

HA! This last month or so I've got my little car (195.6 OHV powered American with twin stick) all dialed in and tweaked to perfection after putting the EDIS ignition in and fixing some gremlins (the bad kind, not the good Gremlins :-) and driving it hard like a madman I got... 18MPG! Lowest I ever got! Driving a lot without OD engaged, revs up to 4000 - 4500 (lordy does it get loud at such breakneck speeds).

It ain't broke, I blame the driver. Couldn't and didn't keep my foot out of it!

This fillup, I'm driving like grandma, keeping vacuum high and revs low, OD in as much as possible. It ought to fall back to 24+. We'll see.

DC,  Your main need is for good tuning of the carb mixture, base timing/ mechanical and vac advance.  A stock motor doesnt need a hotter ignition setup.  It wont hurt of course.  Being rid of points is the biggest ign upgrade youll HAVE to have and you already have that.  You may also want to go to a taller rear tire, but that will hurt take-off  alittle.

If the Duraspark module was on the way out the MSD might improve mileage.
The only thing you can do is make sure the carb is in top shape and settings are right. You should be getting around 20-22 mpg on the highway (cruising 60-65) and 16-18 around town. A lot of that depends on how you drive. If you're cruising over 65-70 on the interstate all the time you will be lucky to get 18 or so on the highway. You're pushing a brick through the air, and power requirements start to go up considerably over 65 mph. That's about the speed at which aerodynamic efficiency starts to make a huge difference -- and there's just nothing you can do about that. You can do a few things to make a minor improvement, but not much.

DocCreer wrote: Ok so i just replaced my Crappy Duraspark Module with a MSD 6a,will this help MPG any?

Dude you keep barking up the wrong trees. Remember we covered all this waaaay back, NO, forget any ignition changes if you have already removed the points and gone electronic. There's nothing you can bolt on (except my uncle Vito's long-lost 150 mpg magic carb the oil companies and governement tried to get away from him. I think he's still on the run - Mr. Finch is helping him out now)

Please go back and re-read - same rules apply today as last month or last year. I know you choose to not believe and want that magic pill, but once you reach a certain place, there's nothing simple left.
The "hotter spark" is all in the marketing - remember we said the engine will only call for 50K if that's all it needs, even if the ignition could possible supply 250KV? It ain't gonna help moving from a good stock coil to a super hot, guaranteed to make you win every race chrome plated gold sealed Indy coil It's marketing hype.

Taller tires MAY REDUCE your MPG! A few folks have found that out when they thought, gee, I'd be going faster, the engine would be going slower and .... instant MPG, right?
Wrong.  Unless the current tires are "too small", going bigger can be a step backwards. It's especially true on smaller engines. If that engine is slowed down a bit while the car is going 65, it may be working HARDER to push the car, and working harder at a low RPM means you have to open the throttle more.. and you are out of the peak or most efficient RPM range for MPG.
Look at it this way - you have a bike with 10 speeds or gears. You hit a hill and work up a good sweat and can just keep your breath, but it's working out ok. Now next time you hit that hill, you shift UP a gear, and suddenly your legs cramp, you can't catch your breath, and you slow down as you just don't have the power to keep up the speed on that hill any more. You've lost mechanical advantage and have to work harder.

Again, I know I'll get slammed like I was in the past - stop looking so hard for that magic pill and believing all you read on the web.
Taller tires MAY work, but MAY take you backwards - if the engine has to be running slower to push that brick through the air at 65 and is now suddenly below the most efficient power band, you lose.
"hotter coils" and racing ignition won't help - not if what you have is working correctly, and it's already getting all the spark it needs. Any more "capacity" is wasted. The engine won't call for it unless the engine is physically in bad shape, or your current ignition is bad.

If you do by chance see a change, it's either due to some other change that happened during the swap, or the other ignition was bad/had issues, or the engine is really worn out and needs a super hot spark just to fire under abnormally bad conditions.
(but next month I expect a similar question will be asked about the latest ignition system advertising guaranteed results and 150,000 volts through 15mm wires.)

IMO, you've hit the end of the line, and asking the same question over each month won't change the answers you get.
If you want different answers, you need different questions.....

OK, I'm prepared for all the flames and nasties I'll get for being so harsh - but if anyone would just do a search for posts on these exact same questions - you'd see we've been this road several times. 
Being a Monday won't change the answers as "cap'n, you cannot change the laws of physics"