I appreciate all this advice...I don't think my intention was presented as clear as I should have made it...I realize that anything with any kind of power will not get me 30 miles to the gallon...I understand.

But id like to be able to go about 150 miles on 14 gallons of fuel. Because that's what i get pushing my 5500 pound truck with my old worn out 305...thats what im used to. Is that out of reach if i want to build any kind of power?

I also realize that your fuel milage also is determined by how much foot you use on your gas pedal

I was also right about getting flamed for even mentioning gas milage on a hotrod site...

So back to the mechanics...What is needed to make traction with my el camino? What kind of ponies could i expect from a stock 396? stock 454?

Also, does compression affect fuel consumption? I am under the impression that a low compression engine is pretty good for the street.