I know the standard Vitaras are a 19 mm wrist pin, but does anyone know if there's anywhere to get a Vitara or some other 8.5:1-ish compression piston that has a 21 mm wrist pin that will work in a D16 block?

 

i think je pistons can be ordered with the 21mm wrist pins. they make custom pistons for engines i build when i need specific piston specs. a bit pricey though. around 900-1000 bucks for the set with the wrist pins and ringset.