Yes, the 1mz is aluminum alloy block, the 3sgte is cast iron, plus the weight of the turbo gearJay-Spec1 said:
Ive had some conversations w/ many of the guys on the boards. Seems that most like to recommend no more than the high-altitude pully on the TRD S/c (5.5psi) The 1mz's stock pistons arn't built for heat. They would be the first thing to go in a high boost situation.
NO! 1MZ swaps, properly done with attention to detail and reliability of install, are not cheap. Especially when you include labor. 100+ hours of labor seems to be the average. And thats not including if you need to fix anything that you already did.
Research my man!, Answers to all these questions have been debated many times. Although, most of the older 1mz swap info is in the dead realms of the Hybrid MKII forum