The truck started out life with a 3VZE 3.0 V6 and an R150F manual transmission. The engine was not running when I bought the truck. It turned out to have a couple of broken rods and a hole in the block. I picked up two different used 3VZE engines with the hope that I could find one good one to install in the truck. I was prepared to replace head gaskets, re-ring and install new bearings, but I didn't want to do a full rebuild with new pistons and machine work to re-bore the cylinders. The two engines would have required that and I didn't want to sink a thousand dollars into a 3VZE so I decided to swap a different engine. I considered the 5VZFE (3.4 V6 successor to the 3VZe) or the 1UZFE. As I studied the possibilities, I determined that the swaps would cost roughly the same. The 5VZFE seems to cost a little more to acquire the engine and less to adapt thanks to factory parts. The 1UZFE seem to cost a little less to acquire but is more expensive to adapt thanks to the need for an aftermarket bellhousing or bellhousing adapter. The 5VZ swap has the potential to turn out like it was a factory option. The 1UZ seems to have enough of a knowledge base and aftermarket support that it can come pretty close to looking and performing like a factory installation. After considering the information I have been able to find so far I am leaning towards the 1UZ. An early engine with 250hp seems like a great pairing with the R150F transmission. And it is hard to argue with a dual overhead cam, 32 valve aluminum V8 that is known as a million mile engine, and that weighs less than the V6 I have now. So that's what I'm here for. I'm enjoying reading relevant posts and looking forward to learning from the 1UZ experts.