Edelbrock Performer on a 318?

[atlantis737]

Hi guys,

I have a '70 Dart with a 318 in it. I'd like it to be my daily when I'm finished working on it, so of course I'd like to improve MPG if possible. I've done my research and found that the best way to do this is let her breathe easier, open up the headers, the exhaust, and all that jazz. I've also seen one guy who says a conservative 4-barrel will improve my gas mileage, but I'm not sure I buy it. Best recommendations I can find for a 4-barrel is the Edelbrock Performer, the 500 cfm model. I think my stock Carter 2-barrel is running about 250 cfm... would I see an increase in MPG's with the new carb, or would I just make her suck down more fuel?

Thanks for any responses.

Jim

 

[Darter6]

Yes the Edelbrock performer works fine for a 318.They even have a kit that is the intake,carb,Valve springs, cam with lifters and timing chain that works REAL good. Only problem with the change to a 4 bbl is the thing will run so much better that you won't be able to keep your foot out of it !! Hence,, will the MPG's improve?? well,,yes and no.

 

[rumblefish360]

Part of the mileage game is the state of tune of the carb AND the distributor timing.
Letting the engine breath in and out as easy as possible is a good start. Headers with a min. Of 2-1/4 inch pipe and a good free flowing muffler along with a good intake like the Performer are great starts.

Now for the carb part of this. I myself have not used a 500cfm carb on a 318. Just 600's. It is in my opinion that if you use a Edel.'carb, use the AVS styled, Thunder carb. The secondary side is tunable for quicker or slower openings.

Now your mention of the 2bbl. Carbs rating vs. the 4bbl. Carbs rating is off base since there rated by way of different pressure drops. Rest assured that a well tuned 4bbl. Carb on a Performer intake with headers and good exhaust well tuned AND timed engine will get very good mileage.

So hence, sucking down more fuel will be your fault if you do not tune it well.
Or keep your foot out of the secondary side.

I also seriously suggest one more item. This item helps greatly in everything they advertise it to do including mileage. A MSD 6 box. OR an equal. The multi spark box helps insure a full burn, use & power return on the air & fuel charge. With all the above and a multi sparking box, you WILL get a full return at max for the air and fuel being used. Since the box is making full use at a greater return, you will use less fuel to obtain the same power and the return of power in the form of mileage.

In an example, my near 4000lbs. '79 Magnum (me and a full tank of gas for surely tips that scale weight) would get a best of 20 mpg's from a stock 360 (except carb and distributor, a 600 Edel. , with dual exhaust off the manifolds with twin cats)
904 trans and 2.76 gears on 26 inch tires. The MSD was a great help. I gained 2 mpg's with the 6A box. You may do better with the smaller engine and lighter car.
Good luck!