? 500 hp out of a Slant sounds expensive and high strung. I think my convertible was well over the 2800lbs mark with the Slant as well, probably closer to 3350lbs.
The 500 horsepower turbo slant sixes I know something about have 8.51 compression, one 4bbl carb and idle at about 500 rpm very smoothly, very much like a stocker. There is only one thing about them that could be considered "high-strung" and that is their requirement for high-octane fuel. They cannot make that kind of power on pump gasoline; they will have detonation problems because of the high cylinder-pressures that exist due to the 28 pounds of boost they run. But, they don't exhibit the kind of driveability issues that exist in a naturally-asporated motor that has a long duration cam and 12:1 compression with the aggressive spark advance curve that goes with it to make it a "full-race" engine... high-strung, if you will.
On the weight issue, mycar is a 4-door sedan with the following mods, that helped lighten it: No gas tank; fiberglass hood; no front bumper; no back seat, lightweight fiberglass front bucket seats, aluminum front wheels; no exhaust system; no heater; manual steering and brakes.
Those mods have made the weight 2,680 pounds. My street-driven, 340 powered 1964 2-door sedan weighed 3,105 for comparison. Convertibles tend to be a little heavier.