Compu cams XE268H question

vntned said
So I've got the 268 in my 72 Dart Custom 318. The motor was completely rebuilt and put in by the previous owner and has less than 500 miles on it. I was told its .030" over with flat top pistons(he couldn't remember the compression ratio), rebuilt J heads (couldn't remember valve size), the aforementioned Comp268H, and then was topped off with the stock 318 exhaust manifolds and stock 2bbl setup. It has true duals and has been converted to electronic ignition too. Stock a904 trans and stall, and stock open 7.25" rear with 2.73 fd. The car runs fine and sounds great, but gets really lame gas mileage for a 318! It's only getting 9-12mpgs in town and driving gingerly.

Now I've been told that that I need to put on a 600cfm 4bbl and decent intake ASAP and that it'd help economy and power. And I was also told that the problem was that the cam was way to much and that is what is killing the economy.

I've got a Eddy AirGap with an Eddy 600cfm carb laying in the shop that I intend on throwing on, but will it help economy or is the cam the culprit?

I agree with Crackedback that the tune is probably off, in addition to the mismatched parts. The Air-gap is a real good intake but it's not going to help fuel mileage due to it's design. The air-gap raises the runners and plenum above the rest of the engine providing an air-gap (hence the name) which increases low and mid range torque, but since it runs cooler it doesn't atomize the fuel as well as a non air gap style intake and good fuel atomization is a necessity for good mpg. With so many unknown's it's kinda hard to say if the cam is too much for it but I'm sure a smaller cam will get better fuel mileage, but I have also seen engines with that cam get 20 mpg (hwy). First check the timing like CB said and do what he tells you as he knows what works best for optimum economy and power. As for the intake and carb, if fuel mileage is the main concern sell the Air-gap intake and buy a performer. The Eddy 600 should be ok for mileage when tuned right. When it comes down to it most bad mpg issues, (providing the cam, heads, compression, intake, and carb are properly matched), are resolved by proper tuning.