Hey guys,
Im buying a new truck this week. It a 2001 Silverado rcsb with a 4.8 5 speed. I've owned a few of these Silverados but never a 5 speed!
I have some big plans such as installing drop shackles and a posi rear with 3.73s etc.

My question relating to the 4.8l engine:
What cam to go with?
Yes I have read up a lot on this topic but I have additional questions and concerns relating to my specific vehicle.
I plan on putting on long tubes and maybe an intake but no other performance mods other than what my questions are about.

If I am installing a cam on a 130k mile engine I should probably have the heads rebuilt as well?
Either that or build a set and swap at the same time as the cam.
That being said this truck isnt going to be a 1000hp drag car. 300-350whp would be great for me. The reason in my brain to do the whole top end in mainly for reliability not just performance.
Should I just get the factory heads rebuilt with new valves and springs then also get new pushrods and lifters to freshen everything up? Maybe a port and polish at the same time?
Or should i get a used or aftermarket head to do this? I know the 799 or 243 heads arent too expensive either.

Or am I completely over thinking this?

There are a bunch of "drop in" cams with maybe just valve springs that are currently being marketed.
Texas speeds Chopacabra for example. (And Obviously im not worried about changing a tq converter)
Is this really a drop in? Is it smart to just drop it in? Are there better options for my application?

Am I just wasting my money and risking my engines life?

Any advice is appreciated

(PS If i go all out with this truck I'll be doing a 6.0 t56 swap. Just wanted a little chop and a few hp for a few bucks in the meantime)

 

You want to preserve as much low-end torque as possible with that small an engine. Any cam with lope or chop will kill low end torque. A small truck cam with about 205-210 intake duration will do nicely in a 4.8.

 

Before purchase I would run a compression test. If the truck was well maintained 130K won't be an issue. I wouldn't mess with the heads at least for now if the compression is good. If a cam is added I would add better aftermarket push rods and valve springs. I wouldn't throw too much cash at a 4.8.
Maybe a set of headers/exhaust since they will work on all 3 gen LS engines. Also a chassis dyno tune with the upgraded cam.

 

okay cool. I was thinking along those lines. Some motors are fine at 130k and some won’t make it to the next oil change. I guess a compression test would be a great tell. Yeah I don’t wanna open up the 4.8 too much but for a few hundred dollars for a cam and potentially some head or valve train work why not. Realistically I’m many years away from saving up for a t56 6.0 swap so 1500$ or so on a cam heads and tune will be good enough for now. I’m already ordering the headers lol.

 

Have Cammotion custom grind a 204/210 108+0 .553/.553. In a 4.8L it'll have a noticeable idle. But with earlier intake valve closing and less overlap than the Norris, it'll be more responsive part throttle and low end torque (less chance of lugging when you're on the highway in 5th). Yes you will still give up some low end compared to stock, but not as drastic (between headers and tune, you might not even notice it, unless you were towing or hauling). On an N/A 4.8L, it'll make close to the peak power as the Norris too. If you have any head work done, mill them to bump up the compression too.

As for the differential, get a Truetrac instead of a clutch posi. Not sure if 3.73s will work very well with the NV3500's steep 4.02:1 first gear. Might make it unusable. Definitely wouldn't go any higher that's for sure.

 

Just be aware that 350whp is unlikely with any cam that you would want to drive around in a truck. You really need to spin a 4.8 to get that with just a cam.

 

I have nv 3500 with 3:73 gears in my 1992 c1500 swap. 1st gear is usable but i wouldn't go any higher on the rear. It is fun doing a 1 to 2 power shift with my setup. You will be around 2200 rpms at 60 with that 5 speed. I test drove a 4.8 5 speed a couple of years ago with 3:23 gears and it was a dog.