Vortec53

Have a 2000 gmc half ton. The original 5.3 has nearly 300k on it so I'm about to start building an engine for it. Gonna get a good used engine identical to mine and build it. I want to upgrade to get more low end torque out of it. I know I need a cam with less duration than one made for top end power. Just looking for some suggestions. Not looking to go too fast, just wanna be able to pull my 24' gooseneck without working the engine so much. looking for that low end grunt that the older 5.7 vortec has, and the 5.3 lacks.

mark21742

Maybe look for a used ls6, or hot cam in the classified section....should be able to get one for pretty cheap. You could also get a hair milled off of your heads to bump the compression up and maybe go in and not fully port, but just clean up the casting in the ports and bowls.

Even though you would be running a small cam you still NEED to upgrade your valve springs...is throw in a set of comp 918 or PAC springs and be done with it.

A big part will also be the tune. I've seen some trucks with the factory tune have timing set at full retard st cruising speed/throttle and not get much higher anywhere in the whole MAP/ rpm range.

batboy

iTrader: (6)

Another good cam that works well with the 5.3 truck motors is the Comp Cams 212/218 low lift plus LS6 valve springs and hardened pushrods. Add a Airaid MIT intake tube, a pair of headers, and then a tune. I think you'd be happy with the results.

chopperman69

iTrader: (-1)

If you're doing a complete rebuild with new pistons and rings, you might as well bore it out and use LS1 pistons. That way you can easily raise your compression and get a lot of extra grunt.

cory32690

U want torque look at either the calspeed and performance 5.3 stroker kit takes it to a 360 ona 3.8 bore or you can order direct from wiseco there 360 stroker kit they pair with k1 rods and crank the cal speed kit

cory32690

Also if u wanna help it move and not be putting the load all on the motor put a bigger gear in it

96capricemgr

iTrader: (1)

So you have to buy a core engine yet right?

Get a LQ4 they are cheap and plentiful, LQ9 if you can find one reasonably priced.
People blame them for the 3/4 ton trucks getting bad mileage but a reasonable person will think maybe the beast of a 4L80E and 14bolt axle have something to do with that. Lot heavier drivetrain you turn in a 3/4 ton. They also tend to have more rear gear and the 4L80 has less overdrive.