While I'll admit that an aluminum head on a cast block has some challenges associated, some of the most durable engines toyota built had them. 20r, 21r, 22r, 1fz-fe, all of the "S" family (3S-FE), 5M-GE, 7M-GE, 2JZ family, 3RZ-FE, 2TR-FE, 1KZ-TE, 1KD-FTV and 2KD-FTV--and that is only the...