How to get 400 or more hp out of my 5.3
 

Hey guys, I'm new to the site and had a few questions.
I have a 2000 silverado 5.3 with upgrades.
Comp cam - ls1 xr275hr, with a .566 intake lift & .568 exh.
Comp cam beehive valve springs
Chormoly push rods
Electric fan
Custom tune by hp tuners
Cold air intake has stock intake and heads.
I was wondering if anyone knew what other upgrades I could do to make at 400hp or more
Thanks.

400 at the crank is easy, 400 at the tire is a little different. Im assuming you want 400rwhp?

Might as well figure LTs, ORY, TBSS intake, depending on heads might want to port/polish/mill. Not sure what the duration of your cam is but you will want something 220 or larger.

This is just from what Ive seen around here.

My 5.3 put down 300rwhp so far with baby 212/.561"/112 cam, heads milled to get about 10:1, cold air intake, efans, and custom catback exhaust through stock manifolds and cats.

The current build is most likely sitting around 275rwhp or 330 to the crank. With long tube headers and some very good heads you might hit 315rwhp or 375 to the crank. You will need a much bigger cam, great heads, and better intake manifold to get 400 to the crank or wheels. Getting 400 out of a 5.3 is not an easy task though more achievable than many will tell you.

What would I have to do to put like a ls6 intake or ls2? What parts are needed besides fuel rails and injectors. Also where the egr valve go because it's goes inside the stock intake.

forced induction with meth

400fw is obtainable depending upon what year the shortblock is. Don't expect to make 400 with an early LM7 5.3 that made 270 at birth.

Big cam, ported heads, FAST Intake, LTs, UD Pulley, etc etc etc will net 400fw...Question is are you looking for peak HP numbers on a dyno or a good setup for a heavy truck????

- Beau @ TSP

i still think 400 N/A through a 5.3 can be done. nobody puts the money into it to make it happen. and i dont blame them. there have been 500 N/A RWHP dyno queen LS1 cars...no reason you cant do 400 with .4 cubes less.

to the point... i think it can be done, but after you spend the money to get a 5.3 to that 400 N/A mark, you could have purchased a 6.0, knocked off 400 HP and spend more than half the money while keeping it reliable and drivable.

you can blow through that 400 HP# with forced induction or nitrous though.

if I wasn't running big tires, big rear diff and through a transfer case I think I would be a little shy but not to far off of 400rwhp, maybe 380 maybe but once I go to a bigger cam I should be a lot closer
in all honesty it hasn't cost allllll that much

BOOOOOOOOOOOOOOOOOOOOOOOOOST


That's my plan. 317 heads on my 5.3 with big cam, head studs, and my Procharger D1.

Yeah, I also have a 2000 ECSB Z71 and I have one of those early 5.3s. Mine made 210 rwhp bone stock, which is about a 25% driveline loss from the 275/285 fw that it was rated at.

Since then I have added a non-intercooled Whipple @ 10psi, PRC 2.5 heads, Comp cam 224/228, Meth, LTs, true 2.5" dual exh, CAI, etc - only to come up to 425rwhp on a fairly conservative tune.

I think mine would make more if the Whipple could keep up - since I added the heads and cam it will not hold max boost past 4500 rpm - it looses about 2-3 psi from 4500 up to 6500 rpm.

But at 146k miles I don't want to push it too much further.

OP -Don't forget to spend some money on the tranny 'cause it will break.