The LQ4 was rated at 300hp whereas the LQ9 (which wasn't available until 2002/2003) was 345hp, for starters. The LQ4 had lower compresion (9.41:1) to the LQ9's 10.1. The LQ9 also has thicker connecting rods as well. The LQ9 has a flattop piston and the LQ4 piston has a small dish to it. So motor to motor, you're better off with the LQ9, but the LQ4
does allow for more boost, since it has the lower compression. There are other differences too, like casting numbers and such, but I don't feel like having to look it up, just to continue arguing with someone over the internet that I don't know that thinks they know everything...
Also, the LS1 in the f-bodies were underrated at (310hp) they were really closer to 350hp, like they were actually rated in the Corvette in '01. As a matter of fact, a lot of f-bodies were putting 300-310hp to the wheels off of the showroom floor. It was rated at 310hp in the non-ram air fbodys because they didn't want to steal any thunder from the 'Vette. That was still a big no-no back then. Just like they did with the GN's back in the day. I think it's safe to say the LC2's had a bit more than 235-245hp when the L98 was rated the same but was lighter, more aerodynamic and still slower.. They FINALLY did away with that rule with the introduction of the '04 GTO. The only difference from the 'Vettes LS1 and the LS1 found in my car was the exhaust, the air box and the throttle body. F-bodies tend to put more down at the wheels then the 'Vettes too, becuse of the Corvettes drivetrain system..
If the 5.3 is such a great motor, then why aren't more people building them? Why haven't I heard of anyone taking their LS1's out of their f-bodies and vettes and putting in 5.3's? And when they DO replace them with another variant of Gen 3 V8 power, it's ALWAYS a 6.0 LQ9 block, and thats only because they plan on boosting it too Hell?
And another thing.. Not all 5.3's are iron either..
I guess I don't know what I'm talking about.. I never owned a car with a gen 3 motor or anything. Nor have I ever built them, worked on them, helped on other people work on theirs, read about them or anything. Thats not my T/A in my sig either. I found that pic on the internet...