Hello all, I知 about to embark on my first LS build, LM7 5.3 out of a 99 Silverado. 288k miles. I知 planning on taking the block, head, and crank to the machine shop to see what she値l clean up too, from research it looks as if I値l be boring it over, sizing is obviously TBD. I don稚 want to bore over to a 5.7. The truck is strictly for street use, no strip use at all.

Parts I知 looking at.

-Scat forged I-Beam rods.
-Icon forged pistons
-arp main engine studs.
stock crank (balanced with pistons/rod combination)
-Melling oil pump high volume/high pressure? Not sure on this one.
-billet timing set.
-TSP chopacabra, with ls6 beehive springs.
-ls7 lifters
probably going to go with a summit hi-ram, and 92mm TB.

does this sound like a decent build? What numbers can I expect to see? Just looking for around 500 hp. I知 completely new to this so please feel free to give me some advice on parts etc!

 

You are looking at wasting a lot of money for no reason. Do some research.

 

first and foremost, thank you for taking the time to read through the list and taking the time to reply. Like I said this is my first build and just want to do it right. Waste wise, referring to forged combo? I致e also thought of just replacement pistons/rings ie the entire kit from ws6 store, however would it be wise for me to replace rods while I知 at it? Looking for insight here

 

If your going NA I'd just get a crate motor that makes that kind of power out the box, unless your planning to go FI

 

FI isn稚 off the table completely!

 

my na 5.3 made 398 on the tire all motor. I could see 500 to the crank but FI would make it get the power much easier. I'm no expert tho man, I'm just voicing my opinion

 

summit racing has some nice forged piston/rod kits as well have used a few sets and they are very nice, if your staying na just a overbore and some nice pistons would be just fine for you. however i really like overkill and the ability to throw a bunch of power at something later down the road. so in a couple years later if you wanted to throw some big boost or a big nitrous kit on it youd be ready too go. and on the oil pump most just use std volume/pressure me personally i always go std volume/high pressure theres no need for the volume but i like more pressure thats just an opinion (most will vary on that subject).

 

do you have any suggestions on a good set of pistons? Should I just keep the gen iii rods going this route? It痴 so easy to go down a rabbit hole while researching, and 200 here 400 there really adds up!

 

first figure out what bore size your gunna machine to, then figure what heads your going with, then shoot for what compression youd like to be around then call summit racing and tell them all of those things and thell help you get the right pistons and rings to match your set up. me personally id go for about 10.5 to 10.9 compression on 93. if your looking to run cheaper fuel back it down a bit like 9.5 to 10.0 or soo.

 

what did you have done to it?

 

Awesome thank you! Just spoke with machinist today, hopefully I値l get this thing pulled within the next week or so and get it up there!

 

What is this motor going to be doing?

What sort of vehicle is it in? What gears? Converter? Tire size? Weight?

Why a 5.3? By the time you spend this whole mountain motor thing on the itty bitty core, you could get a BIGGER BETTER core for so little money, comparatively, that you wouldn't even notice it; except that when complete, you'd have AHELLUVALOT MORE motor for essentially the same $$$.

What head work are you planning? THAT'S where power lives; not in ARP studs and billet timing sets. All those do, is to improve the odds of SURVIVAL, in the event that the HEADS make lots of power.

In short, looks like A WHOLE SHIPLOAD of money, buying things that won't really make any difference, for a "street no racing" motor. Not that it's a "bad" plan, in and of itself; just, there's no convincing argument that spending all that money gets you anything you'll ever notice in return.

 

This...

 

Easily doable on motor with a stock bottom end. I would clean the bores up, new bearings. Spend machine shop and bottom end money on a decent head, like a good ported ls6 or a tfs 220 head. 230/240ish cam on a 112ish lsa with around 600 lift. (Probably biggest that fits sbe) Up the compression to around 11:1 maybe 11.5:1. Fast manifold or a tbss manifold. This should get you between 490-530 crank.

Definitely not any short runner manifold like the sniper, it will be awful for this combo.

 

 

And since you say you are new at this I want to throw a couple things out there.

500hp on a 5.3 is easily doable on motor but it will be a mediumish/big cam for a street car. If this is a lighter vehicle I would say go for it, the engine will be a tad bit soft below 4500 rpm but lighter cars geared properly will handle it just fine.

If this is a heavy car or an SUV or truck, I would personally highly recommend dismissing the hp goal and focus more on average power from 2500-5500. A similar top end but a cam about 15 degrees smaller will fit this just fine.

Only go short runner when NA if you are spinning 7500+. Otherwise, a plastic factory style manifold will be superior.

Get a truck, tbss or ls6 if you are running boost. many reports of fast manifold cracking under 20-25+lbs of boost and the chinesium sniper style manifold literally expand and contract and crack.

Stock bottom end is strong. Imo, If staying na and not stroking it, I would just do bearings and new rings, cleanup the bores and send it.

Boost will easily surpass your goal, if your going to boost it, I would build for reliability and not go to crazy on cam specs. Keep it driveable. Boost will make the power. I would personally build the bottom end with boost just for peace of mind. Many people may disagree.

 

lm7 5.3 block, gen 3 pistons & rods, 243 heads port, polished and milled .030, btr stage 3 truck cam, dual spring 660 & trunion upgrade, 102mm intake & throttle body, e85 fuel, aeromotive pumps with 6an lines with fuel regulator, it had 411 gears at the time in which I've recently changed