[Kraziken]

Newer engine technology

Aerodynamics

Weight


The reason I ask is, if I were to install a new Vortec 350 in my 1991 Suburban, would I see a slight improvement in gas mileage?

 

[Kraziken]

Engine technology helps a little. According to fueleconomy.gov, a '98 C1500 Suburban picks up 1 mpg over a '91 R1500 Suburban. I wouldn't be surprised to see you pick up 1 mpg if you installed a newer 350. Of course, what is it about the newer 350 that gives it the extra mpg: the better flowing heads, the engine management system, or ???

I expect it would take years to recover the cost, unless you had some other reason for replacing the engine, such as the existing engine needs rebuilt anyway.

Yeah, it wouldn't be to save just gas. The engine seems pretty strong. In the event it goes, I figure instead of a rebuild, it would be nice to replace, to get more power, and maybe some better gas mileage to boot.