i have a mail order chip and i get about 10mpg with a 355 241 gears and a 700r4, do you think the chip is buring gas cause it was made for a 342 rear, also what do you guys get as far as mgp goes i am thinking of a diy prom over the winter i wanna see how good my mpg will get

 

2.41s are a ridiculously tall gear, and no doubt are part of the problem, but 10 MPG is miserable. My 454 (TBI, stockish), 5,000#, truck, gets almost 14.

 

is it posible that the gears are makeing me burn more gas

 

Yes.
If you start tuning an engine, you generally move the peak torque up the rpm range, so what was the cruise rpm, all of sudden is lugging the engine. Not to mention that to acclerate the car, there is less torque multiplication, so the engine has to work harder.

By, the same token too much gear also hurts gas mileage.

Like all elements of design there's no free ride, so you have to look for the compromises that best suit your goal.

 

the chip was set up for 342 im running 241 havent changed yet