Okay I bought a 90 k5 the other day to use as a mild wheeling/camping/spare vehicle. Well I have been driving it to work for its shakedown cruise and iv been keeping close tabs on the fuel economy and its getting an average of 18 MPG. Now its bone stock (TBI 350, 700r4, 3.73 10 bolts) but so is my 2000 s10 that is my normal daily driver and gets 21 mpg, so lets compare. The Blazer is running fuel injection technology that is 10 years older than my 2000 S10, the Blazer weighs a lot more than my s10, the Blazer is not aerodynamic by any stretch of the imagination especially compared to the rounded body of the s10, the Blazer is running a automatic transmission which uses more energy while the s10 has a manual transmission, the Blazer has a 5.7 liter V8 engine and the s10 has a 2.2 liter I4 engine (That means the engine in the Blazer is 2.6 times larger displacement-wise than the S10s engine) And it only gets 3 MPG less than the S10 Not that this is a good comparison since it dosn't factor in transmission and other stuff but I figured it up and the Blazer is getting .316 MPG per Liter and the S10 is geting only .104 MPG per Liter Comparatively the Old Blazer is Waaaaaaay more efficient than the new little s10 with all the advancements in technology. I just thought this was an interesting comparison since a lot of people I know ask me why I like fooling with those old inefficient gas guzzlers. I love to tell them about how efficient my 79 6.2 diesel Blazer is. Anyways Hope you find it as interesting as I did.