I'm contemplating an engine swap in my IROC, and the two potentials that come to mind are the LS1 or a 6.0 liter truck motor. I would mate either to a T56. I think that I should be able to get the 6.0 for less money. It seems logical that with a cam swap & LS1 intake, the 6.0 should be able to make more power than a stock LS1. I don't think I'd be giving up much horsepower due to the lower compression, even if I used an LQ4 (LQ9s seem to be a lot less common). he lighter weight of the LS1 would be nice, but I don't think the 6.0 would really be any heavier than the 350 that's in there now.

Is my assumption correct? Will the 6.0 respond well to a cam and modified LS1 ECM? What's the upper power limits for the cast pistons in the LQ4, and for the hyper pistons in the LQ9? Are the better pistons (and accompanied higher compression) worth the difference to find an LQ9? The 6.0 essentially has LS6 heads only with a larger cc, and the block obviously has a larger bore, so it seems like it would be able to make more power than an LS1 with all other things equal.

Thanks.

 

Screw the iron block. 3rd gens are already way nose heavy. Why not take this opportunity to lighten it up a little. 346/7 cuin LS1s can make a ton of power easily.
Mine makes good power with some Stage 1 LS1 heads, cam, and full bolt-ons (check sig for 1/4 numbers at 3525 lb raceweight).
It's a great swap and there's a company that has the necessary pieces to make it fit already in production.

 

It's a possibility, but if this is to happen at all, a tight budget is going to be involved.

The 6.0 with aluminum heads is already going to weigh a lot less than my 350 with iron heads. That combined with no air conditioning and my cowl hood is going to provide a good front/rear weight balance. The additional weight savings from the LS1 is not worth the added expense, and if I can make more power with the larger bore of the 6.0, then great. My main concern is the durability of the pistons in the LQ9 and especially the LQ4, and how they relate to what's in an LS1.

If I can spend this money at all, it's going to have to be done slowly. This means that to begin with, whatever motor goes in stays relatively stock, with the possible exception of a cam swap. If I can get more power out of an LQ9 with a cam than I can get out of an LS1 with a cam, and do it with less money, I'll deal with the 90lb difference in weight.

 

Jim,
Check out the Conversions & Hybrids section at LS1Tech. There are quite a few 3rd gen LS1s running around and a metric ton of swap info for the searching.

-Matt

 

I wouldn't worry about the LQ9 having cast pistons. Keep the motor in tune with a 160 t-stat, and you shouldn't have any problems, especially since you'll be close to stock. Throw a mild cam in the 6.0 with 1 3/4 LT's. That should really wake it up since it probably has a really small cam ground for towing. Should you decide to build the 6.0 later on, it'd be a great foundation for some ported LS2 heads and big cam.

Jason