Yeah, you could build a carb that'd get 30mpg. A 302cu V8 would last a couple minutes, max, running that lean. Lets be honest, we all love to tell conspiracy stories, but don't you think if the technology existed, SOMEONE would sell it? It'd give the company that held/patented it a huge competitive advantage, and no one really cares how much that'd piss off the Saudis.
IMO, hybrids give up too much in the name of mileage. They're light, slow, and overly complex. Give me a pushrod V8 in a 4000lb car, I like to have physics on my side when I eventually get plowed. I do not see myself owning a hybrid car, for a number of reasons. Personally, I love the sound of a big block at idle too much to want one that shuts off at stoplights. Plus, even if I did change my mind, I'd have to debadge it, so my buddies in the Republican party don't disown me

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P.S. the other reason I hate hybrids is the people that own them, for the most part. If you own one for practical reasons, great. If you own one because you're a tree hugging hippie and you want to rub it in my face, screw you. I don't have a "kick their ***, take their gas" sticker on my car, because I've got enough class not to display my outlook on life via the car I drive. Plus, I don't want the Black Attack getting keyed

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Also, most of the people that own/suggest buying hybrid cars are complete morons, engineering wise. I've had a number of people tell me that we should require all pickup trucks to get 40 MPG "cause the Insight does". Don't these morons know that horsepower/towing capacity/"truckability" (for lack of a better word) are directly proportional to fuel consumption? Yes, you can build a fairly efficient V8 (or a turbo/SC 6 or 8, in which you keep power on tap but don't run more displacement than you need), but at some point, you've gotta pay to play.
Sorry about the rant, but as a car guy, GRRRR I HATE HIPPIES. Thanks to those little SOB's, we saw the death of the 400+ cube V8 (although its coming back, thank you GM), Meg's #16, decent paintjobs, and all other sort of things. As a chemical engineering major (I almost took up environmental engineering), I fail to see how the VOCs in waxes, paints, etc, make a huge difference, when we burn millions of tons of coal a year. We're putting all this time and money into catalytic converters, waterbased paints, god only knows what, when investing half that into clean coal technology would see a much bigger improvement in air quality, plus cheaper energy for us (we've got 400 years of American coal left). When you get down to it, most of their antics are feel-good BS, rather than being grounded in real science.