best year of engine to look for in a 5.3

[blazercrazy70]

Just wondering if there is aNY difference in the engines from year to year in the cast block aluminum head 5.3. Other than the year they changed to drive by wire. Is the hip rating all the same on them just looking for some guidance

[TheBlueBomber]

Originally Posted by blazercrazy70

Just wondering if there is aNY difference in the engines from year to year in the cast block aluminum head 5.3. Other than the year they changed to drive by wire. Is the hip rating all the same on them just looking for some guidance

Early Lm7 engines are about 270hp. 2000+ Lm7 engines had around 285hp. The lm4 is an aluminum block version of the Lm7 with around 290hp. l33 is the aluminum block engine that had around 310hp. L59 was a flex fuel motor.

Very minor differences between the engines. All good candidates for some high hp builds.

[Jon01]

07+ has 243/799 heads + NNBS intake and make better power. Get one if you can.

[jessemthompson]

Originally Posted by Jon01

07+ has 243/799 heads + NNBS intake and make better power. Get one if you can.

I picked up a 2007 5.3 out of a suburban. I am in korea and the drivetrain was shipped to my fathers house till I get home. So I have not seen it yet. Did all 2007s come setup with these heads and the intake? TIA

[dayj1]

Originally Posted by jessemthompson

I picked up a 2007 5.3 out of a suburban. I am in korea and the drivetrain was shipped to my fathers house till I get home. So I have not seen it yet. Did all 2007s come setup with these heads and the intake? TIA

2007 was a "crossover" year. The "classic" body style (as GM calls it) had Gen 3 engines. The '07 new body style had Gen 4 engines and is what Jon01 is recommending.

Gen 4 stuff is easier to find with low mileage, but there are some differences and the aftermarket hasn't quite caught up to what they have for Gen 3s.