Engine SwapEverything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.
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how come i dont see more of y'all goin for the 325 or 5.3 liter version of the lq4? it makes very good power and is just as responsive as the 6 liter but weights less. on top of that is about half as expensive! i have certainly changed my mind from the 6.0L LQ4 too the 5.3L LM7... If I cant sway your opinion maybe this carcraft article can:
a lot of the guys have been going with the genIII-genIV blocks recently. I think you'll see more people going for the less powerful version only because they are quite plentiful (meaning very cheap ). Since they are easy to find and cheap to get, there's more money to improve it to similar or better power levels.
I'm still hunting a lsx family block myself. we shall see what the next few days shall bring......
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1987 Trans Am, work in progress
2008 Pontiac G8
Retired: 1984 Camaro "ZF" 2.8L, 1989 Camaro RS
Customer Service Manager, 1A Auto Parts
I was thinking about the LM7 when the LT1 gose south, but around here the 6.0 is $300-400 more. Plus if I have to use f-body brackets,oil pan and so on I belive I'll spent the extra to get the 6.0 the 5.3 is a good choice though.
If anything, the 5.3 is slightly heavier. Forgetting the undesirable pre-'01 versions, all the iron truck blocks use the same water jackets, same exterior, same iron, same everything, except the 6.0 blocks are bored larger, which removes more heavy iron. Yes, the larger aluminum pistons add part of that weight difference back. Both also use aluminum heads, but the 6.0 uses larger valves that are just slightly heavier. Lastly, the 6.0 has slightly heavier counterweights on the crank, to offset those pistons. The end result is the LM7 comes out within 5 pounds of the LQ4. Around here, the 6.0L is only $300 more, but they're in short supply, you have to prepay the entire $800 to get on the waiting list. Screw that. Especially if you want forged pistons, just have the 4.8/5.3 block bored. I've already taken one 5.3 block to 4", no problem.
Around here, the 6.0L is only $300 more, but they're in short supply, you have to prepay the entire $800 to get on the waiting list. Screw that. Especially if you want forged pistons, just have the 4.8/5.3 block bored. I've already taken one 5.3 block to 4", no problem.
"I've already taken one 5.3 block to 4", no problem." That was gonna be my next question! Very cool, so for my purposes the 5.3 would be better anyway cause im obviously going to bore it. Now, would it be better to play it safe and only take it up to 5.7 total displacement? And I am of the understanding that the '03 or above is the way to go.
Stopping at 3.903"-3.905", depending on pistons, is the smart move if you're trying for much more than about 500 HP, but going to 4" is proving safe making 492 HP @ 6300 rpm. Also stop at 3.905" if you're going to turbocharge, supercharge, run nitrous, or use it in a high-loasd application such as a work truck. Pre-'01 versions should be avoided. If you decide you want 4", have the cylinder walls sonic-checked first, to be sure they're thick enough. Pre'01 blocks need to be tested before trying for 3.898", and can NOT go to 4".
). Since they are easy to find and cheap to get, there's more money to improve it to similar or better power levels.
