I don't know what made him want to swap to another motor but he's running a built, twin-turbo lexus 4.0L V8. Its the 1UZ-FE which is the precursor of the 5.3L, 500hp n/a V8 they are currently using to power the Soarer's in Super GT. These motors are able to make 1000hp+ on pump gas at only 20psi. Its been video documented check the second video. These motors are cheap as shit, strong as hell, able to withstand abuse, are getting a good aftermarket, lighter and shorter than 2JZ-GTE's and make more power. And they'll rev to over 11,000 RPM. :rock:

The video immediately below is of the Ferrari F-40 running a road course. Listen to the engine sound and it's note. Doesn't sound much different than a Ferrari V12.
http://www.1uzfe.com/Web%20F40%20Going%20Hard.wmv

This video below is an engine dyno of a built, twin turbo 1UZ-FE tuned with an Autronic SM4 that makes over 1,000hp on pump gas. Good shit.
http://www.1uzfe.com/bromsning.wmv