Don't bring Smokey's adiabatic engine into this. You're comparing apples and oranges because Smokey's engine was a completely different design than what we're talking about here. I worked for an industrial engine manufacturer that developed 22:1 AFR lean burn gas fueled engines in the 80's and I did the control systems for them. These engines worked, and achieved great BSFC and made good power, but they were also NOx monsters, just like Smokey's......
The density of any fuel decreases as it's heated, and so does its calorific value. This has been proven time & time again in engine testing labs, and is the reason OEM's went to voltage controlled fuel pumps, and eventually to returnless fuel systems.
If you want to redesign your 1UZ to be an adiabatic or lean burn engine, and try to copy some of what Smokey did in the 70's then you might find that heating the fuel/air charge might be a good thing. For the rest of us, running conventional engines, heated fuel is NOT a good thing if you want to make power.
Here's a schematic of Smokey's engine; although it's in the public domain at the US Patent Office, credit goes to the Gale Banks website: