I’m looking for suggestions on a 450-500 HP build for my 6.0. It had lost compression almost a year ago and I did a piston job on it. What I want to do now if make it close to 500 HP. My current parts is a comp cam, a set of 799 heads, 8.1L injectors, an HP Tuner, and possibly some shorty headers if I can see any benefit from them. It currently has wiseco pistons in it
the cam I plan on running is a Comp Cam XFI RPM Cam 54-412-11 the specs are
Advertised Duration 265/271, Lift .522/.529
I plan on reusing the lifters and push rods since the engine only has 160,000 miles and they haven’t been making noise. Since it is my daily I don’t want a race cam because like I just stated it’s my daily and I use it for towing so I want more low end power and torque

 

You’ll want to get some boost or stroke it. Shorty headers are a waste of time go long tubes

 

You want to look at the duration at .050"

That cam is a 212/218 114 LSA. Its a solid cam that a lot of companies make and similar to what i put in my motor. I don't think its enough cam for more than 400 whp.

You need a NNBS/TBSS intake manifold, cold air intake, 1 7/8" x 3" long tubes, 10.5:1+ compression and a bigger cam if you want to get to 500 whp.... IMO

 

if you know of another cam that won’t have a lot of lope or very high lift let me know. Ide like to have good torque and power from 1500-6k because I use this truck for towing. Basically I don’t want a vey high lift or very choppy cam ide like to avoid valvetrain noise of the higher lift cams. I’m okay with some chop but I just don’t want anything crazy because this is my daily and ide like to keep it kinda quiet. As for stroking it or boosting it that’s out of the equation it’s too expensive for me. If I can get a little over 400 I think I’ll be happy

 

OP,

This is one of those combos where we’d pump the brakes a bit and make sure expectations line up with how the truck is actually used.

A 450-500 hp N/A 6.0 is doable, but it’s not going to happen with a mild towing cam. A 212/218 type cam is great for what you described, strong low end, smooth manners, and good for towing. It just won’t get you anywhere near that 500 hp mark.

To realistically push into the mid 400s and beyond, you’re looking more at a cam in the 22X intake and 22X to 23X exhaust range. That brings more power upstairs, but it also means giving up some low-end. It typically requires a converter and possibly gears to really work well, which doesn’t line up great with a daily driver tow rig.

The other big piece here is your compression. Do you know which Wiseco pistons are in it? Dish volume will affect your compression ratio, and that plays a big role in what cam will actually work and how much power you can make.

From your post #4 it sounds like you’d be happy in the low 400 range. That’s a much better fit for your goals. A mild cam in that 212/218 range with your 799s, a good tune, and supporting mods will make a strong, responsive truck that still tows well.

With a setup like that, 400 hp at the crank is a realistic target on a healthy 6.0. If you’ve got flat tops or a small dome helping compression, that only works in your favor with a cam in that range. The stock exhaust will be the limiting factor though. It may still get close, but long tubes and a good free-flowing exhaust will make it a lot easier to get there and let the combo work like it should.

On the header side, shorties really aren’t going to move the needle much. You might see a small change, but nothing you’re going to feel. If you’re looking for a noticeable gain, that’s where long tube headers and a free-flowing exhaust start to make a difference.

If this was a customer coming to us, we’d be looking at something like our SUM-8719R1 (.550/.550, 209/217, 112+1, -11* overlap) as a solid option. Ideally though, the SUM-8728R1 (.600/.585, 212/218, 110+3, -5* overlap) would take better advantage of the 799 heads and the rest of the combo.

Both of those would also benefit quite a bit from a more free-flowing exhaust.

We get it though if you’re trying to keep this build budget-friendly and stay at .525" lift or less. If that’s the case, we’d at least recommend stepping up to an LS6-style beehive spring or similar. It’s cheap insurance and helps keep everything stable.

Let us know what pistons are in it and what direction you’re leaning. We’ll be happy to help you from there.

 

so the mid-low 400 will definitely be fine for me. I just need more than the puny 200 it has. I mean the 01 corvette made 400 if I remember correctly. The pistons I have in it are the wiseco pro tru street pistons PTS523AS, if I had done more research on my motor and knew Chevy made it with such low compression I probably would’ve got small domed ones to help boost compression. I have a set of comp springs picked out too that I forgot to mention they are the 26915-16. I have a freshly rebuilt NV4500 with 4:10 gears. I like to hold 5th going up hills or 4th when possible. The truck just doesn’t have enough torque or power to make that happen. I really need the extra power when hauling my tractor or bigger machinery as I tow anywhere from a few thousand pounds to a few tons.
my revised parts list is looking something like this.
HP tuner
8.1L injectors
Cam
Valve Springs
BTR rocker arm upgrade kit
799 or 243 heads
ls6 intake
possibly milling the heads .30 and getting a slightly thinner MLS head gasket

 

Not sure where you're coming up with this... the LQ9, a 6.0 w flat-tops and larger-chamber heads than you have, was "rated" by the factory at something like 345 HP and 380 ft-lbs FWIW, and had about 10.1:1 compression. With the 243/799 heads and the same bottom end, you'll end up with about 10.6:1, which is pretty much ABSOLUTELY ALL you can run on the street with pump gas and a towing load. It would be making closer to 365 HP and 405 ft-lbs, with a stock cam and exhaust manifolds. With the cam you have, you'll lose a little low-RPM torque (the peak torque may be higher, butt the RPM at which it occurs will also be higher, leaving lower torque at very low RPMs like take-off from a stop), butt gain some HP. Long-tube headers make a SIGNIFICANT improvement; probably 20 - 25 each HP & torque.

You DON'T need to be trying to raise the compression any further if you intend to tow with this thing, especially not with a stock converter. Also, a truck intake is more suited to that purpose than the LS6; I'd leave that as-is. Injector upsizing is a good idea, as the stock 4.8/5.3/6.0 injectors (they all used the same ones) are about 29 lb/hr, and are all butt totally maxed out in a stock LQ9. The 8.1 ones, or flex-fuel ones, are good upgrade choices. I'd suggest a converter upgrade LONG BEFORE an intake change.

 

400 horsepower comes at 6200 rpm. I sense that you are thinking that the increase will be across the entire RPM range, that only happens with forced induction, or increased displacement. A positive displacement supercharger will give you what you seem to be thinking that a cam will do. Any cam that boosts horsepower will at best not reduce low rpm power too much.
The only 6.0 that I can think of that was rated less than 300 horsepower was the engine that they sold for a generator set. I think it was rated 175 horsepower, but at some absurdly low rpm.

 

You posted while I was typing and typing, RB04Av.

 

I don’t have an lq9 I have an lq4 that made 325 HP max. I don’t need a converter because my truck has an NV4500. I’m just looking for good power and torque that happens below 4k and up to 6 if that’s possible