I have a 03 Silverado with a 4.8. right now its procharged pushing about 13lbs. and has headers.idk a lot about head or cams and ive read around some forums hoping to find some answers. im wanting to do some more to the motor and I have a buddy who will sell me a set of 6.0 heads at a reasonable price. so heres my questions... Ive read that the 241 heads on the lS1s are pretty good because they'll drop the compression ratio down on the 4.8s. im wondering if id be better off with some 6.0 heads or 241s. im debating about using a z06 cam in it. any input or advice would be appreciated. thanks

 

I wouldnt do either unless you planned on running more boost. Both will lower your compression ratio from what you have now.

 

I wouldn't worry about the heads. Under boost the efficiency of the heads increases dramatically. However a good cam will increase power pretty dramatically. Swapping cams to say.... 214/224 .571/.574 LSA 115 would make for some good fun. As mentioned you shouldn't lower the compression unless you plan on a lot more boost.

 

Thanks for the input, its greatly appreciated. Eventually I want to get it up to around 20lbs. would I see a noticeable difference if I put some heads on there even if they were milled down to keep compression the same? The motor is a turd and I'm wanting to get more out of it and a cam is a must.I was thinking of bigger injectors as well.

 

a good set of flowing heads would be a great investment imo if you have the funds if not then a cam first as said above, its not all about home much boost you can run but also the volume, and if your going to throw more boost to it you wouldnt want to raise the compression anymore,
what your fuel system like as of now, and its a turd? i figured 13psi would be a blast, im on 8 right now with my 4.8 and its a blast, who tuned it?

 

More info on why your motor is a turd?

I would go with Jarrett's ISKY triple 12 cam if it were me. As mentioned, under boost, heads wont make a huge difference. Plenty of guys making big power in boosted applications with stock heads.

 

Thats not really true...badass heads will make a lot more power than stock heads at the same boost level. Same rules apply to FI as NA in that regard.

 

fuel system is stock as far as I know with exception of having a inline pump put on it. I replaced the one in the tank with a walbro 255 when it went out. once I get some boost built its really fun but until then theres no power. it hasn't been tuned since ive had it and that's one of the next things on my list but the guy told me to get the mods done first.

 

Im confused, you say until you build boost its a , how long does it take you to build 13 psi, I figured it wouldn't take a procharger very long to build boost since they are belt driven (of course I know slim to none about them). Just out of curiosity do you have a wideband if so whats the AFR are doing while driving, cruising; wot just before boost; and at full boost; etc etc., and if your gonna do a cam and or head swap wait till you do that to get a retune, unless its never been tuned before which im gonna guess isn't healthy running 13psi on a stock tune,
Give us an example of your turdyness
when you go wot does it bog for a minute then spool and take off,
does it cut out until a certain rpm then take off?,

 

How can you talk **** about how it runs? You don't know what injectors it has. You haven't seen the tune. How do you know it's even running 13 pounds?

Don't throw more mods at it, before you even know what's going on with it. From what I've seen, 4.8s handle boost well and make good power with it.