scottm078

Good morning everyone, I'm looking for advice on my eventual LS swap. I bought a donor car its a 98 z28 with a t56. It has 159k on it and runs and drives fine. My question is should i swap in the ls1 from the car or trade the engine for an lq4/9? I would like to do a H/C/I and be in the 450ish RWHP range. I'm more interested in torque than peak HP. From what I've read with the 98 its easier to get a 99+ wire harness and pcm. If I keep the ls1 I would like to use an ls6 intake and ls6 ported heads with a cam. LQ4/9 I could still use the same heads and intake. I don't think the weight would be too much of a problem. the iron block weighs about as much as the one it would be replacing, plus I'm not tracking or racing the car. its going to strictly be a street car.

aliceempire

iTrader: (14)

I don't think either are a bad choice. End of the day the 6.0 has slightly more power potential from displacement and a bit more durability due to iron block. But neither of those reasons mean much, they'll both be 450hp range with relatively similar powerbands. It's only 18 cubes. As far as torque band goes, my 04 LS1 with 203k on it can move the car from a stop in 5th gear without stalling immediately, and my GTO weighs more than our cars. There's enough slow speed power to go around when built accordingly.
Personally, I'd stay LS1 but the only downsides to a 6.0 is more work to acquire one and sell the LS1 and 100 lbs added to the front end. Your choice at that point.

JAYDUBB

You can run the LQ4 (hopefully 2005+ because of the better rods) or the LQ9 for the higher compression and better rods. Throw LS3 heads and intake on it (better flow), cam and let it eat. Im doing a 2006 LQ4 and LS3 heads (turbo build). The Gen 4 rods (2005+ and ALL LQ9s) are stronger and have been used in 1000 hp builds regularly. The engine dyno record from what I have found is 1500+ (Gen 4 LY6). It was done by Richard Holdener. My G8 (L76) puts down well over 400+ rwhp so you should be able to easily make those numbers with the LQ4/9 with stock LS3 heads.

QwkTrip

iTrader: (22)

LQ4 and LQ9 are gen III engines. I didn't know they ever got the better rods from the Gen IV engines....

aliceempire

iTrader: (14)

I had also seen that late gen 3s had gen 4 rods but I have no proof to it. I did look into if my LS1 could have them without pulling it all apart. My official answer is I don't know.

QwkTrip

iTrader: (22)

LS1 does not have Gen IV rods. Where do you learn this silliness?

JAYDUBB

All LQ9s all have the better rods, according to the part numbers...

2002 Escalade LQ9, item #23 https://www.gmpartsdirect.com/v-2002...engine--engine (remember, the LQ9 debuted in 2002...)

2005 Corvette LS2, itme #23 https://www.gmpartsstore.com/v-2005-...engine--engine

2008 Corvette LS3, item #23 https://www.gmpartsdirect.com/v-2008...engine--engine

The 12649190 connecting rod was made for the LQ9 truck engine in 2002 and GM decided to put them in all of the 5.3, 6.0 and 6.2 engines from 2005 until the Gen 5 came out (2005+ 4.8 rods are longer BUT STILL Gen 4). LSA and LS9 rods are different, of course.

JAYDUBB

Around mid 2005 and up. Best way to tell is to check the exhaust manifold and intake valley bolt head size or pull the pam. 2006 definitely has the better rods.

QwkTrip

iTrader: (22)

Yep, I see what you're saying now. Looks like the term "Gen IV rod" could be a misnomer. Maybe it's really pressed pin rod vs. floating pin rod. And the LQ9 was an early adopter of the floating pin rods?

Or did the Gen IV really have a different rod design as well?

aliceempire

iTrader: (14)

but 2002 LQ9s did?...which is what lead me to search it out. Again, I have and had no proof in either direction. I pointed out that I had heard what was being referenced.

QwkTrip

iTrader: (22)

Well, heck, I don't know what to think now. It took you people all of 10 minutes to break my confidence and leave me lost and confused.

JAYDUBB

LQ9 had the 12649190 rod and floating pins first and then GM put them in all of the V8s from 2005 until the debut of the Gen V. 2005+ 4.8 rods are longer and LSA and LS9 rods are totally different.

scottm078

Thank you all for the replies and I'm glad for the side bar about the rods (helps me feel better about my decision.) I didn't need much convincing to go with the lq9. Just a quick search and I see one nearby for about $1000 with less miles than on my ls1. I plan to sell the ls1 and use those funds to do an lq9 with l92 heads, ls3 intake, and some kind of cam. strait used parts (for the most part) I'm hoping to stay around $3000-3500 for everything. Hopefully I can sell the ls1 for close to that. 500 plus hp engine for practically free sounds good to me.

JAYDUBB

You should be able to find a set of 5364 heads for DIRT CHEAP. Some dont THINK they are LS3 heads but BASICALLY they are. And look for a L76 intake from a G8 or a Caprice PPV (Bonus if its a PPV intake with the injectors.... Its the same thing but again, most dont know that its BASICALLY an LS3 intake. Watch the price difference. You will be amazed.

scottm078

Thank you JAYDUBB, that's exactly the info that I'm looking for. I'll start looking around. I'll have to do research about what to do about a throttle body and maf. I would like to stay dbc and I believe all the gen 4 stuff is dbw.