Hello fellas. This will be my first LS engine build. My 5.7 in my GTO decided to give up on me after a track outing this past weekend, my fault i'm sure. I think I leaned it out too much. O well. Happens.

I've been having a spare gen 3 aluminum 5.3 on the stand for almost a year. My Plan was to build it and have it ready for when I have an issue, but I always procrastinate. Now after hurting the motor, I'm forced to do something. So after much contemplation and changing my mind and going back and forth on what I want to do, I decided I'm going to do a built bottom end vs a stock gen 4. One of my wise buddies (hes much better with money than me and seems to have better luck with stuff because he believes in do it right the first time) made a good point to me. I told him I was gonna stick the 5.3 in and build my 5.7, then swap them. He asked if I really like swapping motors or if I'd rather do it once and be done. Well I dont like pulling motors, so one and done sounds better to me. Plus its less money because if I do a dirty rebuild on the 5.3 then build the 5.7...thats two engine builds I'd have to pay for. So thats my reasoning for it, and I feel like it might be a little more forgiving if I rattle it (which how i'm building, you'll see I'm thinking about fuel choice and detonation).

So heres my plans. And I welcome any constructive criticism, if you are wanting to just be an ***, just think twice before you do it....because there no need for it. I'm always ears to ideas that have good reasoning or experience. I dont mind spending money (actually yes I do lol) for things that make my life easier or make things better. I'm hoping to make 800+ whp eventually, this engine should give me room to grow and not worry about it.

2004ish gen 3 5.3 aluminum block
Summit PRO LS Pistons and H beam rods 2000 arp rod bolts
-7cc Dish, 9:3:1 compression, 6.125 rod, longer than stock
ported 243 heads, probably going to do 6000 ferrea valves in them and get rid of the stock valves
JP racing single billet roller timing chan set
Summit Ghost cam
Clevite P series main and rod bearings
Durabond coated cam bearings
Stock oil pump, ported
factory oil pan gasket, timing chain and fel pro rear cover gasket and seal
Saccity Corvettes Billet dumb bell
Lifter: I think i'm gonna go with the morel drop ins

I decided on lower compression and a longer rod because I'm running pump gas. Past long rod motors I've built that were NA seemed to be more detonation tolerant and I'm hoping this helps this motor. Every little bit counts, right?

So as I get parts and do things, I'll post pics and my thoughts. I'm excited about the summit rods and pistons, they look like high quality parts from what I can see. My rods are on back order so it'll be a couple weeks before that stuff is here.

 

Here’s my grungy motor. It came out of a 2004 Buick Rainer. Yuck. I’ll finish stripping it this weekend and clean it up. I planned on a quick ball honing.

 

can't you bore the 5.3 to a 5.7 then you will be basically putting a forged 5.7 back in it?

 

why tho? The negligible amount of power lost from going smaller can be made up with 1 or so psi. Plus boring a block adds $$$ to the equation and the cylinder walls are perfect as it is

 

Agree...but you made it sound like you wanted a 5.7 back in it. Or perhaps I misunderstood you...either way I agree with your friend. Build the 5.3 and do it right the first time.

 

ok I see where you’d think that. But no, either one don’t matter to me. My reason for building the 5.7 was because I didn’t want to spend the money right now to do all that right before Christmas and I have my wife’s birthday (today actually) and one of my kids b day’s right after Christmas. Then I just bought my 15 year old a truck and bought $1500 worth of wheels a couple weeks later. Then I just bought my youngest one a small 4 wheeler. Whew. So I just wanted to recoup some money before building an engine. But, think about this. $200 for the gen 4 rotating assembly (buddy was giving me a deal) then rings, bearings, gaskets, lifters, timing chain, etc etc....put that in and then start that all over again on another engine, just didn’t make financial sense. I won’t lie, I’m having a hard time with the fact that I’m stepping down in engine size, but it doesn’t matter. It’s gonna be faster. I’m building this one to hold 18-20psi or more and all I really have my 5.7 was 12. So it’s definitely going to be a step forward. And maybe this engine will not use fuel at idle like there’s no tomorrow.

I have to keep telling myself that my buddy’s car went 8.90 with a 5.3, while I’m not planning on going that fast, it gives me hope and justifies the money I’m spending.

 

So I'm doing basically the same build but 1/2 head studs, and O-ringing the block so I never lift a head .

Only critique.

Dont port your heads. Stock casting heads do not need to be ported on a bolsted application. It's just a waste of money . Stock ports flow more than the deck of the head can take . Basically you'll blow the deck of the head out before you need a better flowing head .

 

they already ported. My thought process is the more I can make on the motor, the less boost I’ll have to use.

my buddy had (just sold) a 4th gen with a sbe 5.3, ran 30psi on arp head bolts, Felpro mls gaskets and it runs 8.90 at high 150’s. I was following his lead on that. I’m not really looking to run more than 18-20psi. Well that’s the plan. For now. Lol.

 

If you've already got them, run them. Any gains NA is magnified in boost. I.e. if you would gain 20whp NA, and want to run 1.5 bar of boost, that's like adding 50whp. Sure you can just run another 2-3 psi, but free gains are free gains.

 

So, why can't you just build the 5.7 the same way you are planning on building the 5.3? You say that you hurt the 5.7. Is it so bad that you can't rebuild it? If it was me, I would put forged internals in the 5.7. There is no replacement for displacement.

 

well first off, the cylinder walls are thicker on the 5.3

then I’m kind of in a hurry, 5.7 isn’t out the car and I CANT take it out right now. I’m building another turbo setup for a buddy and I have to mock it up on my car.

I’m hoping to get a little less fuel consumption with the 5.3....the 5.7 does suck fuel badly. I drive the car a lot.

I have the 5.3 on the stand torn down already. Parts already ordered for it. So I’m locked in

I hope that the 5.3 has a little less tq so my drivetrain has a better chance at survival


and no replacement for displacement? Well this comes to mind.....

 

This is why I want to put the ferrea valves in it and open them up a little more.


Has anyone wondered why a new mustang is ridiculous fast with a blower or turbo? Cylinder heads.

 

Agree... they don't have enough bore to utilize the heads potential NA.

 

If you already got em thats different. I thought you were going to buy a set of heads lol

 

nah, gonna use the one I have. Hoping I’m not making a bad choice with lower compression.

 

If you're only running 93 you're making a good choice.

 

Good. Hopefully it won’t be too lazy but I could probably counter that by adding some timing down low.

 

Arp main studs? Or reuse stock bolts?

 

I'd stud it . $250 for piece of mind

 

No E85 in your area?