Thanks for all the replies.
I guess I didn't know where to look to see this thread again, I actually thought it just didn't work so I kinda made a new thread too.
Ya, it seems like getting the money back in gas mileage might be so far out in the future as to never actually arrive.
Any thoughts on just running kinda high rpm's on stock rebuilt 1979 454 with an Edelbrock carb (not sure about cfm)... ... what rpm could it handle for hours on the highway (Colorado to California)?
I guess the only really low budget option is rear diff gears and taller tires when I need tires again.
How much towing capability would I lose going from 4.56 to 4.10 or 3.73?
thanks ya'll,
I appreciate the input