4.8 Cam ideas

[Oilbrnr]

Any thoughts on a cam that would help a 2007 4.8 with 243 heads that is going into a K5 with a SM465 manual? Only other mods I have planned would be headers.

Thanks!

[Shon]

you want down low TQ or high end power?

[Oilbrnr]

Low ft/tq, at least as much as the 'lil guy will put out.

[Shon]

"old man cams"
these will be in the 218 intake duration. or the LS6/Z06 cam.
great low end and easy to drive around on. Not going to get alot of lope out of it but you will know its there.

[Liddy71]

I am buying 4.8 .a guys got for sell it only has 5000 miles on it complete and 4l60e top to bottom wiring and computer out of a 2003 truck .he's in a bind for money how would it do in a 2wd k5 what would be some mods that could be done to improve it. for the 500 he asking I can spend a little on

[LEEVON]

comp xr265 212/218 .522/.529 on 114lsa.

[Super73]

You mention low RPM TQ. At what RPM do you want this thing to STOP making power? You could put a custom cam in it that will pick up even more bottom and TQ than the off the shelf cams suggested, but, you will most likely not have the valve events to pull a lot of RPM. Performance trends Engine Analyzer is a pretty awesome program and I could put your combo in it and spit out a custom cam for you. I just need to know:

What Shift RPM you would like?
Stock 243's? Stock springs? Willing to upgrade?
What headers are you going to run?
Stock 4.8 truck intake?
Stock throttle body?
Are you ever going to have to pass a sniffer test?

[Oilbrnr]

Hmm, being that it is a K5 with a manual transmission, I'd probably say the 4-5k would be the max shift point. I really hadn't considered doing any other mods, other than springs if required by the cam. Oh and some LT headers, to which, I think there is only one manufacturer out there (Pacesetter) that makes some that will fit a 4x4 application. (even then, I don't know if they will work with a manual trans).

It will be sniffed, but to 1977 standards for the truck, which shouldn't be hard to reach even with significant tweaking. Err, at least I assume.

I'm just looking for fairly easy gains, if there are some. I suppose I could leave it stock and still be ahead over the 350 that is in there now.

[Shon]

Originally Posted by LEEVON

comp xr265 212/218 .522/.529 on 114lsa.

on of these FS on PT.net

[Oilbrnr]

^^ thx for the heads-up, but it is sold...

Would that cam require diff. springs?

[Shon]

cam and springs go together!!

[LEEVON]

Keep looking, the pop up fairly often, but go quick because they're popular. LS6 springs are perfect for these, I paid between $50 and $60 new for a set if I recall. Won't hurt to upgrade the pushrods too. Searching high and low this seems to be the best cam for a 4.8 with bolt-ons while retaining low-end torque and driveability.

[Super73]

IMO, I'd look for a 02+ Z06 cam with some 1.85 rockers and comp 918 valve springs. It's going to idle better and most likely produce more bottom end than a bigger cam. While you are at it, get an adjustable timing set and try to set the intake center closer to 108. It's still going to want to rev to 6,000-6,500 or so..

[Liddy71]

2003 silverado 2wd 4.8 4l60e what ratio rear came with it from the factory . i check my 72 rear end and its a 308 how would do and would it work . I have a 373 6 lug not sure what year it is . it really pitted bad

[Liddy71]

the pitting is on the out side never saw one piited that bad the inside look good

[Oilbrnr]

quite the Hijack ^^

[Liddy71]

ok sorry about that I'll Quit

[Oilbrnr]

No worries! I just didn't want to get too far off the cam track. ;-) Finding good info about the 4.8 is IMHO somewhat more difficult that the other bigger engines unless you want to do forced induction. (which I don't)

Consider this though Liddy, the 4.8 on paper comes out ahead of the original 350, and that is without an sort of a 'tune'. A gear change after doing an engine swap is fairly trivial if you find the performance not to your liking. For the price, I don't think you'd be disappointed.

[Clyde65]

I have a 4.8/4l60e with 3.08 rear gears and it works just fine. It isnt a speed demon but I dont want that anyway, if I did, I would have gone with a 6.0L. The LSx trucks came with 3.42 with the 4.8 so we are close to that. On the HWY I get around 20MPG, but I also havent gone very far. in city I get about 13MPG.