My Truck

Nikon02 · 12-29-2005, 10:43 AM

I have a 4.8L Silverado. My ideas was to run an ls6 cam and patriot heads combo with a few other changes. My questions is would this work? what power gains could i expect? how would this effect my mpg?

Nikon02 · 12-29-2005, 11:11 AM

I was also thinking about maybe ls6 heads also. Any ideas or inputs would be great.

white1 · 12-29-2005, 11:47 AM

Stick with the 4.8/5.3 heads (patriot or whatever) but get a bigger cam than the LS6. The LSA is a little too much for our trucks. something in the 114 area would work better. Most of mine (ive been through a few) were 112, or 113, or 112+4*. Also a 300 or so stall will really wake it up. With a 4.8 I would stay around 220-222 on the cam, and it will definatly need some tuning. You can go a little smaller, but I wouldnt go much bigger. My favorite cam I had in my 5.3 was a 218/224 on a 113 LSA. in my 6l I have a 223/226 with a good bit of lift, and am very happy with it. In my opinion, your best bet would be to contack Cam motion, or Allan Futral and ask them for recomendations on the cam.

Nikon02 · 12-29-2005, 11:52 AM

I am a diffrent guy. I like taking what i have and making it alot better. i want more power but i am hopping for an increase in fuel economy also. I currently get about 20 mpg on the hwy. When i run with 5.3s i can beet them after we get going i just dont have any low end. I want to improve greatly throughout my power band.

**hammertime** · 12-29-2005, 01:26 PM

Originally Posted by Nikon02

I am a diffrent guy. I like taking what i have and making it alot better. i want more power but i am hopping for an increase in fuel economy also. I currently get about 20 mpg on the hwy. When i run with 5.3s i can beet them after we get going i just dont have any low end. I want to improve greatly throughout my power band.

If mileage is a primary concern, definately err on the small side for your cam selection. Something like comp cams XR265HR or the XR269HR has a nice 114* lobe separation, and less than 220* duration @ .050" to keep the PCM happy. You might find some additional power and performance through a good tune, but Comp claims the 265 needs no modifications.

Also, with a cam that small, you might find that optimizing your exhaust (headers, high-flow converters, cat-back) would net you the same gains as a cylinder head change on that small bore. White1 is correct to recommend staying with 4.8/5.3 heads.

Good Luck & let us know how it turns out.

Nikon02 · 12-29-2005, 01:35 PM

Well it is the same bore as the 5.3. (just a differnt stroke) if i got a cam for milage like one of the ones reqomended above, would there be any power benifits as well? how much? would an exhaust and head change also make a big diffrence?

**hammertime** · 12-29-2005, 03:39 PM

Originally Posted by Nikon02

Well it is the same bore as the 5.3. (just a differnt stroke) if i got a cam for milage like one of the ones reqomended above, would there be any power benifits as well? how much? would an exhaust and head change also make a big diffrence?

Yes, just smaller bore than 5.7L or 6.0L engines. Even the smallest of cams should give you a decent power gain over the stock cam and over an LS6 cam. LS6 is still just 207* intake duration @ .050 and an OEM wide 117* lobe separation. The XR265HR would likely give you a gain of about 20-25 hp over stock. Ported and polished 4.8/5.3 heads should give you at least that, up to about 30 hp for a nicely done set, and full exhaust & pcm tune would likely net you something like another 30-40 hp. Don't quote me on those numbers( flywheel, not rear wheel ), as not than many hot rod 4.8's, so I'm just guessing. But I'm not trying to blow smoke up your ass either.

Small cam; small good flowing heads; reasonable sized primarys on a full-length header with exhaust to back it up and a decent tune could net you almost flywheel 100 hp over stock without compromising driveability, mileage and response. Figure 60-70 hp at the wheels.

Good Luck!

Nikon02 · 12-29-2005, 03:55 PM

so the xr265hr and a set of 4.8\5.3 patriot heads and a set of headers should bring out close to what was mentioned above?

white1 · 12-30-2005, 04:14 AM

If you want to stay all motor, Id get a good small cam 216 or so, a good set of heads, some LTs and exhaust. About the best thing for the 4.8's is a good stall. They definatly have no low end torque.

**hammertime** · 12-31-2005, 10:23 AM

Originally Posted by Nikon02

so the xr265hr and a set of 4.8\5.3 patriot heads and a set of headers should bring out close to what was mentioned above?

Should be close. Also, stall is a good suggestion as long as you don't tow anything to heavy. Definitely invest in a good trans cooler if you get a converter in your truck.

What is your rear gear ratio?

Nikon02 · 01-02-2006, 05:52 PM

I have 3.73s and i also want to keep it a daily driver, so i dont know about the stall.

**hammertime** · 01-02-2006, 06:01 PM

Originally Posted by Nikon02

I have 3.73s and i also want to keep it a daily driver, so i dont know about the stall.

3.73's are a pretty good gear for a car. Your truck likely has a pretty tall tire. With a 29 in tall tire, you're only turning 2100 rpm's or so at 70. Switching to 4.10's would only bump that to about 2300.

I would consider either a converter or a gear change based on whether or not you tow anything. Gears will also help your pulling power loaded by getting the revs up a little, where you should run a lock converter in your daily driver - so the stall wouldn't help you there.

white1 · 01-02-2006, 06:46 PM

I have a custom grind cam in my truck 223/226 with an undisclosed amount of lift

I had the cam ground around my 4wd usages (alot) and a 3000 stall. The converter was kind of loose and stalled to about 32-3400 in my truck. It was borderline for a daily driver, but the worst part was the exhaust resonance. I have that taken care of now, and if I would have took care of that before, I would have had the converter refurbished and still be using it. I have a TB converter (I-6 trailblazer) and it stalles to about 25-2700 behind my 6l, it is tight, cant tell a difference between it and the factory till you stand on it. If you get a good converter, it won't be a problem for daily driving duties. Im probalyl going to get a 3000, or 3200 Fuddle or Yank because I still need a fairly tight converter for when Im offroad. Dont be scared of a converter till you actually drive a truck with one. I always was, now I think a converter and cam will be my first mods from here on out.