Ive been reading up alittle on some cam choices for my 06 5.3. To begin with, this truck is my daily driver. Ive been looking at this for a reference: http://www.compcams.com/technical/Ca...07/172-175.pdf

From what i understand, is the XR265HR probably my best bet? Give alittle down low, but give more pull in the mid range and upper range. The XR259HR i dont know about, sounds like it might be too much down low and not give me much mid range and better pull. Is the XR265HR the choice i should go with? any opinions or recommendations? thanks guys

 

Why don't you??? And how about using the search... These cams have been covered in pretty lengthy detail...

 

Here's the way I see it, comparing the 3 cams mentioned (206/212 .515/.522 112, 212/218 .522/.529 114, 208/212 .554/.558 115), and assuming that they are intended for a stock 5.3. The XR259HR will have good torque down low due to it's shorter duration and tight lsa, but the torque curve will not be as broad as the others due to their wider lsa. It can be used with the factory converter and will provide a noticeable improvement over the stock cam throughout the powerband. It will pull to 6k and will be kind to the valve springs due to it's low valve lift and less agressive cam lobes.

The XR265HR has been used by many and is a proven performer. Alot of guys have run it with the factory converter and been happy with it. I would recommend at least a 2600 stall converter to optimize the powerband of this cam, but that's just my .02. The longer duration of this cam compared to the XR259HR will move the powerband higher up, and the wider lsa will provide a broader torque cure. Once again, the low lift and less agressive cam lobes will be kind to valve springs and allow you to use the tried and true yellow LS6 springs. Of course if you talk to a Comp rep they will recommend their springs only.

I'm not very familiar with the XR261HR15, but I like the specs on it for a daily driven truck. I'm sure that most would shy away from it since it's short duration and wide lsa will not provide the lopey sound that they're looking for. The wider lsa should provide a very broad torque curve, and the higher lift will fill and evacuate the cylinders quickly. I'm assuming that these lobes are more gressive than the others due to the higher lift with lower duration, and should provide nice cylinder pressure which = more power throughout the powerband. This cam seems like it would work fine with the factory verter, but I would probably run it with a mildly stalled converter (maybe 2400?). These trucks seem to respond well to higher stalled converters, even in stock form from what I've read (haven't driven a stock truck with a higher stall converter so I have no first hand info).

There's a cam sticky somewhere, maybe over at LS1Tech, that has alot of good info on camshaft technology, it's very informative.

Hope this helps

 

Another thing to add, if your concerned about which cam will sound the meanest, the XR265HR will have the most lope as it has the most overlap, due to it's longer duration and 114 lsa. The XR259HR has the tightest lsa (112), but not alot of duration, so you won't hear it very much, especially if it's tuned properly. With the right tuning you can make it sound stock. I have that cam on a 114, and it sounds basically stock to the untrained ear...I can hear it, but I know it's in there, and I consider my ear "trained" by now lol. I would assume that the XR261HR15 would have a very mild idle due to it's relatively small duration and wide lsa.

Just a note on lsa...generally speaking, as the lsa gets wider, the powerband moves up, and the torque curve gets broader. A tighter lsa will have more torque down low but the torque curve will peak sooner.

 

@budhayes regarding the cam you have...theXR259 on a 114LSA...
if you have to put numbers to it, what RPM range would you give the powerband? at what RPM does it really start to pick up. i was recommended this cam on a 112 by comp and i'm curious to other people's experience with it. my truck is a DD with some light towing but i'm wanting to lift it and go to 35" tires so i could use more torque down low and a nice broad torque curve.

 

Jetsey, I have the XR265hr low lift on my truck and it's perfect for a DD. You're not going to loose anything downlow as this is an off idle cam, there's a dyno graph in an old thread that shows gains are considerable from 3000rpm all the way to the red line.

I wouldn't go any smaller than this for a DD.

 

Look here

https://www.performancetrucks.net/fo...d.php?t=435536