First off, I want everyone to know I tried the search function here but just couldn't find the information I needed. I have a 04 RCSB 2wd truck with a 4.8 and 5speed with 3.73 gears and its black (we all know black is the fastest color) But anyways here it goes. I am just looking at doing a simple cam swap over the factory cam with no other mods. The only info I can find on the current 4.8 cam I have is that it has a .274/.268 lift but nowhere can I find info on what the duration is at .050" or what the lobe separation angle is. What I am looking at is a Comp Xtreme RPM LS1 cam which is cam # 54-408-11 and the specs are 206/212 .515/.522 and 112 degree lobe separation. They rate the powerband as being from 800-5800 RPM's and in the description they say it's a "very strong torque cam with good mileage and noticible increase over stock cam". Now keep in mind they base their ratings on the LS-1 (350CID) and this will being going in a 4.8. This well tend to shift the powerband ratings up a bit since the motor with the smaller cubes won't swallow that cam up as well. I want to stay with a cam like this for the reason I plan on doing no future mods. All I have right now is a Diablo power tuner and the cam swap is where I'll draw the line. I can't justify buying a radix when I can get a new 408 stroker for cheaper than what guys are paying for the supercharger alone. That's down the road for sometime later. But for now all I want to do is the tuner/cam swap and with a cam that small I shouldn't need to do any exhaust modifications I wouldn't think. Also the 5-speed and lower gears should be to my benefit. Basically what I'm trying to get out of you guys is, I need to know for certain what the factory cam specs are on the 2004 LN4 4.8L motor and I'll go from there. I would think if I went with this comp cam that I shouldn't need to do any extra tuning. However the lift is almost twice as much and I don't know about the duration yet. (what I need from you guys). Keeping everything stock other than the tuner, would someone like to make an educated guess as to what would happen as far as horsepower goes? Do you think I could expect to see 20RWHP increase? Also, what would happen with gas mileage? Up or down? I get 24MPG straight open road driving now and 20 in town. Any loss of low end power with this cam? Any noticble lope? This is my daily driver so I can't have something crazy (that's what my '70 chev truck is for). I want smooth power from idle up to 5500 RPM's but would like to have an increase of torque. Sorry if this post seems long winded but I'm just looking for some educated responses. Thanks!

Joe

 

wish I could help ya, but here's a bump!

 

hp up
gas mileage down
I believe it would have some lope being its a manual

IMO I would go a tad bigger
maybe like the low lift 212 218
or the vinci 047

I love my 062 but I wish I woulda went larger

 

I think that is a good cam choice. The only change I might make is opening up the LSA 1-2* just to make idle tuning easier. The stock 4.8 cam is the same as the 5.3 I think. I'm not sure if it has changed any in the last few years.

 

I run that cam in my F-body. Idle on a 4.8 will be lumpy. Eallanboggs runs that cam in his 4.8. Check out his reply #5 in the following thread: https://ls1tech.com/forums/showthread.php?t=170903

BTW, the cam does behave exactly as described by CompCams in my 5.7

 

I have the exact stock cam specs at home, but from memory its 190/191@.050 with somewhere in the .450-.475 range lift on a 119 or so LSA.

 

Can someone verify for me the factory cam specs for certain before I make my choices? I didn't think the lift was anywhere near a 400 lift but in the mid .200's

 

The lift is definately in the 400's.

 

Lift :Intake .457
Exhaust .466

Duration: Intake .268
Exhaust .274

 

yeah go for the 114 lsa not the 112 i have just put in a 212/218 in my 5.3 has a mild lope but none too bad and i havent had the chance to get it tuned yet so im sure that will help i also wish i would have gone bigger but with that cam you might also consider the zo6 cam just a little more duration i believe is like 207/219 i think and it idles bone stock and makes great power