I can vouch for this... When I had my cam ground, comp forgot to put 4° advance into it. I really didn't want to wait to get it running so I installed it. I has decent low end because there's enough lift to help compensate, but it doesn't really pick up until 5500rpms. After that its just a monster. Great for a roll race where someone wants to run to like 140, because it'll walk away from nearly everything on the street. But towing...I wouldn't expect a whole lot. Best to sell the heads and use the cash to buy a cam ground for towing, IMO. That'll do wonders

 

Stock for stock, the LQ4 makes more torque down low than an LY6, which is essentially what you would be building. I've talked to guys who have ported the exhaust on the heads and cammed the engine differently so they can get more down low, but that's a lot of work to make a setup that isn't optimized for torque a torquey setup. I drive LY6 trucks at work every day, and we switched 90% of our fleet from LQ4 trucks (the rest were 8.1s). I can tell you that the LQ4 rigs offered more down low and the LY6 trucks like to be revved. It makes for a bit of a pain in a truck that large. My DD is a 6.2 L92 Silverado, and it's a riot, but if I could change one thing it would be bottom-end torque. Once I give it some revs, it gets really fun, but it doesn't give you the off-idle torque that the more truck-oriented 317 combos do. Plus, as Dezert1500 is saying, you could sell your L92 components and put that money into your ride and you'll come out ahead anyway.

 

Dezert1500, what did you do to gain low-end torque over your 317 setup?

 

I would second this. Look at the SAE power numbers for both engines. (disregard the different scaling)

 

It's only 200 rpms different from peak to peak but it feels like so much more in practice. What gives? The torque below peak looks fatter on the 2010 too.

 

great info guys...thanks....i think im gonna go with the 317s maybe mill them a bit to bump up compression...re ring the block along with new bearings...upgrade the cam...and sell the L92s...

what do u guys think? any other suggestions?

 

I wouldn't touch the 317s. The power gain isn't worth the trouble.

With the money you would get for your l92 top end, you could pick up a nice set of used, ported 243s.

I put down 404/391 with a 230/236 cam in a lq9 w/ stock 317s. Here's my dyno thread : https://www.performancetrucks.net/fo...esults-472581/

You probably don't want to run a cam that big. But I can tell you, it has plenty of torque down low.

 

I could be wrong, but I believe that is a function of VVT. It increases the dynamic compression on the low end.

 

I get that the point of the VVT is to offer the best of both worlds. What I don't get is how it says it has more low-end torque but doesn't feel like it in practice, even with the fat first gear of the 6L90E vs the 4L80E.

 

which is interesting because given equal rear end gear, the 6l90 has almost 64% more torque multiplication than the 4l80 off the line.