You want low end torque right? That cam you have is ALL wrong for that use.

My idea for your build. Keep the 5.3 bore, find a 4" stroke crank. Buy the Wiesco pistons for the 4" stroke, if the connecting rods are the floating style OEM pieces they should be fine (as long as you get the correct pistons). That will give you a total displacement close to what a 6.0L has, yet with the added advantage of a smaller bore to promote more efficient combustion.

Get those heads worked, there's a bit of torque that can be worked out of those through port / valve work, plus reshaping the combustion chamber smaller to up static compression. With the combo of piston you buy and chamber size, I would try and get it up to at least 10.5:1.

Camshaft wise, keep the intake valve closing point as priority number 1 (as this affects dynamic compression which is what will actually have the most affect on torque at low rpm as there is more time per stroke and less intake force (aka "natural supercharging effect") to resist the intake charge being pushed back out of the cylinder on the upstroke of the piston. If you want low end torque, you're not going to want this to move (later in the compression stroke) too far away from stock. 206-208 degrees duration with the lobe having the most lift you can stomach (idle warm ups before higher rpms / frequent valve spring changes may be necessary). That will help extract as much torque out of that 4" stroke 6.0 setup as you can.

 

Yep, 5.3 and torque monster just don't go together. Look in the big scheme of things, even 364 ci (6.0) is small displacement. The cam and 5.3 you have in the OP are a recipe for disaster.

IF it was me, I'd try and find a good junkyard 6.0. Put in a fetal cam (210/218), 14:1+ compression on E85, BEST heads you can afford (trickflow, AFR), Fast truck intake, and a huge 4 or 5" air intake. 1 7/8" headers, no cats, and a 4" catback.

 

5.3 casting heads on a 4" stroke 5.3. or 243s on a 427+ ci. Custom specd cam. Stay away from hogged out heads.

 

1 5/8 doug thorly tri ys 1.8 yella terra rockers slp udp cai.

 

200shot nitrous off idle...

ok i kid..

 

 

budget tq 5.3L build here is what I did.

All bolt ons in my sig 281 rwhp 336 rwtq with 31" tires on 20" rims

After my milled .03 stock 862s (9.8 compression) vinci 210/218 .551 .551 362rwtq that's a 26rw gain
A little less lowend tq 1500rpms under compared to the stock cam stock cam. With your gears the truck is always going to be in the power band with this cam. 332rwhp 51rwhp jump truck is a totaly different animal that sounds stock with the 116LSa

Leave the intake runners alone. Tq comes from high air flow velocity NOT volume on lil bore motors.

Put flat top 4.8 pistons in and mill the heads .03 and .04 cosmetic gaskets you'll be at 11:1 compression

 

I would start with CAI UDP Longtubes with y pipe and 3" exhaust for tq and custom premium tune see how you like that. This set up easy 300-320rwtq on stock wheels. I would start off buying stuff that will work on a 6.0 and 5.3

Your 40" tires are going to kill power

tq cam 5.3L will make close/lil more to the same tq as a stock 6.0

6.0 LQ4 average low mile cost $800-1500. You can sell your 5.3L for $400-500

Of course if you cam the 5.3L and it is still not enough you could just get a 6.0 later, stick the cam in it, put the stock 6.0 cam in the 5.3L and sell it.

SOOOOOO many options man. I would make a list/flowchart of all your options with power gains in relation to $$$$$

 

What do you guys think about putting a set of milled .03 4.8/5.3 heads on a LQ9 to bring compression to almost 12:1?

I know the intake valves are and runners all smaller which would kill top end but do yall think it would turn the 6.0 in to a low end tq monster?

 

It would prolly make good power down low, but it wouldnt flow very good. and i hope you would be tuning it and not on 87oct