I am starting this thread to discuss gas engine technology focusing on efficiency with a power secondary. After many fill ups on my 1988 V3500/th400/4.10s with a 454 I have determined that careful design and thought could provide several if not more MPG. Currently my truck averages 10.1 MPG empty at 65 MPH on level ground. I am hoping to discuss changes like: engine, transmission, gear ratios, fuel management and even theoretical improvements like head chamber design and quench areas. As I have very limited funds this will be a long project. I will start with listing my current focus in no particular order: 1. True dual 2.5” exhaust with hi flow mufflers and no cats, stock manifolds 2. Electric fans to replacement stock clutch fan 3. MSD 6A ignition (only because I have a free one) Below is a list of ideas that I believe will help but will probably never be able to afford: 1. Roller CAM 2. Flat top pistons to optimize quench area and raise compression (lots of discussion here) 3. Wide band O2 sensor and custom EFI computer (I have a MegaSquirt custom EFI controller to try out) 4. 4L80E Overdrive Things that claim improvements but I have doubts: 1. Throttle body spacers 2. Injector spacers 3. Just about anything TurboCity sells 4. Intake gaskets with a fine mesh to atomize fuel How about it, what do you guys think? How about some good web sites that already focus on this?