I keep seeing this thread pop up in "New posts" and every time I get ready to contribute, Cable has already covered it, and then some! Nothing more to add other than, thank you Cable.
As already covered, the label “Truck engine†vs “Car engine†means squat diddly other than what variant of the LSx family the engine started life from! This also applies to other monikers as well. People that pass judgment on a power plant based on the term “Truck†vs “Car†without actually looking into what those differences really are, is.... not to put to fine a point on it, an idiot! It's a shame there are so many of these "computer engine builders" out there, blindly trying to persuade others with their uneducated ill contrived bias/judgment as fact because their feable little minds inability to open and get passed the fact that the term “Truck engine†does not automatically denote an inferior power-plant, perpetuating more automative performance myths that many newbs trying to glean as much factual tech as they can, buy into!
Ok, enough ranting…
My personal experience on the topic, having gone with the 5.3L LM7 as the interim choice for my LSx project, long term powerplant to be based on the 6.0L.
I have also found price to purchase an LSx outright, the truck engines, in particular the iron block 5.3L are generally much easier on the pocket book. As Cable mentioned, there were more 5.3L engines produced than all other LSx RPO's combined! Weight of the iron block vs aluminum block variants being around 65-70 lbs, (all else being equal, cranks, damper, FEADS, intake, exhaust mani's etc). Depending on what FEADS one needs, (GM speak for Front Engine Accessory Drive System), and how resourceful they are using eBay, Craigslist and the various LSx forums, the truck power plants can still come in for less after being re-outfitted with the car FEADS than a comparable car LSx with the needed FEADS already on it. For some that only need the water pump and alternator, (no A/C, no P/S, etc) it is even easier. Used items for the LSx can be had for good prices. Some examples of deals I have ran across are; F-body LS1 intake manifold for only $55 shipped. Picked up the 0968 grind LS1 Vette cam with LOW miles, (.500" lift, 115.5 LSA) for only $65 shipped. Brand new LS6 take out lifters for $110 shipped. Brand new LS6 yellow, take out valve springs for $55 shipped, etc. As Cable pointed out, when going for a cam swap wanting to use OE cams, the '02+ LS6 cam is a good choice, especially over the milder '01 LS6 cam, (same duration, lift and LSA as the LS2 cams).
Do beware when placing WTB ads as the scammers/thief's are prowling the WTB sections of the car forums. I got ripped off trying to source the milder '01 LS6 cam for my little 5.3, known documented scammer/thief Ernesto Gonzales Castillo found my WTB ad for that cam, contacted me Via E-mail, we carried on several E-mails back and forth, he even supplied picture of the cam with the casting number, I paid for it never heard from him again, then a little research found this;
http://www.ls1tech.com/forums/negative-trader-feedback/818849-scammer-alert-ernesto-gonzalez-castillo.html
Too bad I didn’t search first.
Truck LSx, great bang for the buck, OH yeah, especially if the buyer is resourceful in acquiring the other necessary hardware/accy needed for their conversion project.