If someone were to be mechanical inclined that has aluminium heads laying around then yes, that would pay off.
I read somewhere that for every 100 pounds of reduction of weight from a car you can get 2 to 3 % boost in the MPG.
Wonder if they can make plastic casings for AC compressors, alternators, that can withstand the heat and just as strong as metal casings ?
How about the weight of a full tank of gas compared to 1/2 a tank of gas ? 1/4 tank of gas ?
What would the numbers be then ?
I know 1 square foot of water weighs about 64 pounds so ? what would 1 square foot of gas or the volume of a full tank of gas weigh ?
Well of course if you can save weight effectively for free that pays off. Someone who has to investigate to see if lighter heads are available, as you stated in the earlier post, would probably not be able to do it for free though.
I used to be a pretty fair shade tree mechanic back in the '70s and '80s, but I would not trust myself to do a major teardown and rebuild on one of today's cars.
And BTW I like lightweight cars. Have driven Alfa Spiders, tweaked Karmann Ghias, and my current fun car is a little rocket ship called a Honda S2000.
But you won't find too much love for lighter cars here on FR. "I like me a big heavy armor-sided monster cuz it's like, safer if you get t-boned by a Peterbilt, herp derp....."