It's not sensible by any means, and if you already have the V6, it makes as much sense as having a shoe that is 5 sizes too small... You really like it and you already own it so, you cut your toes off so the shoe fits your foot... Not to mention good luck finding any even modestly high performance parts for one of these engines... But, to each their own. We won't judge (too much

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How about a 1UZ or a 3UZ-FE Lexus motor? Mated to a CD009 manual 6-speed? Lots of hop-up parts for those and pretty sure no one's done that before, though I might on my next build, or a 2JZ with twin turbos... Lots of performance parts, dual overhead cams, 4.0 / 4.3L V-8, amazing reliability and performance and you can get stock parts anywhere... and the 1UZ/3UZ weighs in at 430 lbs... Some have installed the Eaton M90 supercharger on top, super easy swap, and then a re-tune of the ECU and 500 hp...
And still has the SBC firing order too
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Just sayin', if you want to do something different, you could put anything under the hood, but make it make sense to do. I mean, the weak GM V-6 weighs a bit more than a BBC 454 with iron heads...