Hi Guys,
I know many of you aren't the right people to ask, but here's my questions:
I'm planning to build a 305 SBC for mileage only. Power is secondary, 200HP are easily enough. I want to make 16-17 mpg in a lbs 5000 G20. I know it's possible, people before me have also managed.
I just want to know which of these statements are true:
1. roller rockers decrease internal friction
2. lighter rods and pistons save gas because they decrease the weight the engine has to accelerate in different directions all the time
3. a shorter stroke slows down the piston speed and gives the same effect as #2.
4. porting, headers, large manifold chambers increase the airflow, the engine has to do less "pumping" so less efficiency is lost this way
5. balancing the crankshaft will stabilize the whole engine and cause less energy to be lost in vibrations
6. Aluminum heads will dissipate the heat better but will not help in getting mileage
7. Aluminum block and heads will save weight, but not enough to make a difference in mileage
8. decreasing vibrations, internal friction and the weight of accelerated parts (also in the valve train) will get me higher efficiency and slightly higher power, but lower torque.
9. going for low RPMs at mid compression (under 9.5:1) is going to be more efficient than running high RPMs in high compression (over 10:1).
9. so I go with Aluminum pistons, forged conrods, a stock 305 block and ported heads, an EFI, high octane fuel (I'm planning on 105 octane LPG) and a cam designed for efficiency.

Is that going to get me good mileage?
Please tell me which of these assumptions are wrong, gas costs $5 per Gallon here in Germany and I want to keep my V8 van. (And I need something new to play with )
Thanks a lot, MadMax