Has anybody done a complete rebuild on a 5.3/4.8 ? Cant seem to find anyone that has done this on a truck mostly bolt ons, only LS1 5.7's. Having a lot of difficulty making a cam selection. My truck is a daily driver so i dont want it stallin out on me but I want some nice grunt to it. I am going for 400 plus hp on straight motor any suggestions?

 

Is that FWHP or RWHP?? For RWHP you'd need a h/c 5.7L or 6.0L motor. You MIGHT get 400 FWHP out of a 5.3L, but you'd need a set of p/p heads as well.

 

Some artificial aspiration will net 400+ to the wheels.

 

I plan on having heads ported and polished, springs, Ti retainers, ferrea valves, etc. also a z06 crank, workin on gettin forged pistons(if i can find them) with some good long tube headers and a good intake system i should be at 400 hp correct? I have a ram air hood on my truck like the firebird hood and i planned on fabbing up an intake that came straight out of the throttle body and sealed tight to the hood when closed. Anyone see the new lightning concept? I want it very similar to that. I just dont know what happens when it rains, what do they do on the f- bodys so you dont get water in? Any suggestions, I really want to make the power with my 5.3 liter I already bought it. So if i dont have to invest in an LS1 to get a lil more power thats fine by me.

 

Is the LS6 crank different than the LS1? Didn't realize that.

 

I forgot to mention 1.8 or 1.85 roller rockers, i have seen some more agressive cams that say not to use those though, any idea why? I hear the roller rockers ad upwards of 20-25 hp.

 

I think the stock rockers are already rollers.. just at a 1.7 ratio. Definitly not sure on that first part.

On a stock cammed engine, the 1.8's will probably net that, because they generate more lift.

The two problems that come to mind:

If you're running something like the comp cam's with the XE lobes, (anything over like, .550 or so) - they have too steep of a ramp to be compatible. The 1.8 rockers are really just imitating what the cam with the larger lift is already doing. I think it comes down to the valve springs or the valves themselvs not being able to handle that kind of work.

With too much lift (XE's and 1.8's), you could also be in danger of having piston to valve contact.

 

so its not worth the money to change out the rockers? will thew sotck rockers handles the incresed hp? especially if i decide to supercharge or turbo? i have seen the stock ones and they are a roller i guess but they look pretty pathetic compared to sftermarket, stamped steel with a ball bearing on the end of it, not really a roller, just a ball.

 

Those are some good questions there... a little beyond me.

I know with all of the cam installs I've read about for trucks, there is no absolute need to change out the stock rockers. I actually haven't come across any yet that really recommend it. I think you'd have to start turning some serious RPM's with a large cam before you'd have to. Again though... this is getting beyond me, just responding with what I've come across on here.

 

400RWHP sounds a little optimistic but I think if you threw all you could into the build-up you wouldn't be too far off the mark. Ported and polished heads that would raise your cr to 10.5:1 with large valves and a LS6 cam and intake would be a good start. From there, every known bolt-on (headers, ported TB, pulley,etc...) would get you a very powerful but still very driveable ride.
I think you could go crazy with a cam and get another 30 ponies over the LS6 cam but it ain't gonna be a very streetable truck anymore.