I'm interested in building a high compression 5.3L, but weight is an issue. I hear the aluminum block 5.3L is called the L33. I can get just about any 5.3L easily, I just want to know more about my options.

I've done some searching, and I have some LS1 experience (one H/C build), but I haven't reached any specific answers to what I'm interested in. I'm not a noob when it comes to the hands on, I've just been all over the place and have a lot of general knowledge.

1. How big of a bore can I go in the aluminum block? I know the LS1 I was involved in was considered a 347, is it similar where you can't really go with a big bore?

2. How high can I rev it? Obviously some darn good balance/blueprint is needed, but can I hit 7500rpm regularly?

3. I know the LS1/6 heads will bolt up, but in comparison what direction should research I more? Is there a FAQ somewhere that breaks down all the stock head options? Is there a quick and simple explanation of the 241, 243, 317, etc, stuff? Is an option to upgrade to the newer ports or should I stick with the cathedrals?

4. At what point would it make more sense to suffer the 80lbs of the iron block?

5. Crank universal? Meaning it will bolt up to a flex plate or a flywheel?

I guess I should clarify my goals:
- I'd like to be able to put down at least 375rwhp, preferably 400.
- I want to get some "high" revs out of it
- I'd like to keep the build (outside of balancing/blueprinting) pretty cost effective. As in ported stock heads, valves, springs, LSx stock used cam, rods and pistons. I'm not looking to spend a fortune.

If I can avoid buying parts labeled "LS1/LS6/etc" to keep some of the green in my wallet the better. Thus the interest in the 5.3L

 

I can answer a few of your questions. No need to change the heads. They're very similar to the LS6 heads. The L33 is pretty much a 5.3L version of the LS6. Same heads and cam. You can upgrade to L92/LS3 heads if funds allow. If your goals are 375 to 400, porting the stock heads with a very streetable cam should make that easily. Not sure if you can safely bore the L33 block to accept LS1 size pistons. I did that on a 5.3 iron block and it worked fine at 10psi and about 500rwhp. It would still be running except for a slight connecting rod problem that trashed the block.

If you can find an L33 in good shape, I wouln't do anything other than clean it up, port the heads, and add your choice of cam. It should make your power goals and live long. Addressing your desire to spin the thing to 7500 rpm.....er..uh...I wouldn't without forging the bottom end. At least pistons and rods. Crank might be OK.

The L33 should fit anywhere and bolt up to anything an LS1 or LS6 will.

If you're going to "build" this thing, you won't save much if any over building an LS1/6. The only savings I can see is the initial cost of the motor. If the L33 was in need of a rebuild, I wouldn't fool with it. Pistons, rods, and crank would all be pretty much the same money. Forged pistons for the L33 might be hard to find. That's why a lot of folks bore the 5.3 blocks out to LS1 specs. You can find forged LS1 pistons as cheap as stock cast 5.3L pistons.

 

That helps, thank you.

I worded the original post poorly, the valvetrain, pistons and rods would all be upgraded. The stock portion's of the build would be block, crank and ported stock heads.

Since I'm looking at putting in new parts I would obviously be "rebuilding" the engine, so bearings, rings, etc would all be new. I'm guessing that's what you mean by "cleaning it up".

I'm considering the iron block, despite the weight, as I can get a "drop out" engine assembly with all the accessories for $675. It's higher mileage, like 100K, but that just means the block is heat cycled a whole bunch and stronger.

The SCAT/Mahle(3.905) combo we put in the LS1 seemed to be pretty strong, but I wasn't the one making the financial decisions on that build. I doubt I want to spend the money on Pauter's(my preferred brand), if the SCAT's are more the sufficient for my goals.

What rods were you running? Boost isn't an option at this point, but it would be interesting down the road. Ideally the engine I have in mind will be going in a stripped out BMW track car/weekend warrior.

 

An engine like you're planning ought to be sweet in a light car. I was lucky and stumbled upon an L33 to replace my son's engine that broke the rod. His truck had the stock 5.3 bored to 5.7 specs with forged LS1 pistons. Rods were stock. I'm sure it would have lived a long time at 6psi, but we thought, with the forged pistons, 10psi was safe. I didn't think about the stock rods being the next weak link in the chain. Live and learn I guess. The L33 we found had 33K miles on it for $600. We just swapped out the motors and put a lighter spring in the waste gate. He's about 7psi now.

Have you considered an LQ4 or 9? If you're going iron block, the extra cubes of the 6L sure make getting the hp easier. You get the LS6 type heads with either engine. I think the 9 and the later 4's have a little better rods too. Stroke is the same as a 5.3 or 5.7, so it should rev just as easily. If you go that route, make sure you get a 6.0 with the aluminum heads. Some of the earlier ones had iron heads. Good luck with your build, sounds like a fun project.

 

I have considered the 6L. I'm concerned with the "buy in" price, plus the added mods.
Basically both engines would be "drop out" engines(full accessories) from a wrecked vehicle. I have a hook-up per say. It's ~$675 for the 5.3L iron block, or $1100 for the 6.0L.
Both the LQ4/9 and the Iron/Alum head 5.3's are really close to the same weight right? Externally they're all the same, I can't imagine the bore would make a difference with weight.

The 6L LQx block is an option, but I thought the 6L has the 4" stroke vs the 5.3's 3.622"(92mm). I might be getting them confused though.

Another idea I had considered is a 6L block and 4.8L crank to make a 328CI. That was a serious consideration because I don't have the car for it to go into yet, and a BMW 328i is an option. I was thinking about a small window vinyl(2"x8") reading "328CI in a 328i", or something clever but similar.

Around here junkyard stockpile 5.3L, so replacement blocks/cranks is "cheap". The 6.0L is twice as much for a short block.

EDIT: The only benefit I see from running the LQx block vs the 5.3L in comparison of "buy in" cost, is lower cost in machining as the bore is the size I would be upgrading to. 4" to 4.030" is cheaper than 3.77" to 4.00", or at least I would think so.

 

Your junk yard guys are rapists! Either that or my local boys are extra good. I paid $1200 for an LQ 4 with 6500 miles on the clock. It's been running well in my mp122 radix blown truck for 10K+ miles.

There's some that think boring the 5.3L to 5.7 is risky without sonic testing the cylinder walls for thickness. I've never heard of anyone boring a 5.3 to 6.0. Maybe I'm wrong on that one and someone will correct me. The bores for the three motors are 3.78, 3.9, and 4.0 respectively. I think you're a little confused on the various engine's strokes. 5.3, 5.7, and 6.0 all have the same stroke. The 4.8L has the shorter stroke with a 5.3L bore. A 4.8 stroke in a 6.0 motor would make a rev-easy LS. 5.3's thru 6.0's rev pretty easy with the slightly larger stroke. I'd hate to lose the cubes. I'm old, but not old enough to have coined the phrase, "There's no substitute for cubic inches". Truer words were never spoken.

 

I understand the desire for more cubes, but I'm not after all that much power. I am after an easily revved V8 though. Moving a 3600lb full weight F-body is more difficult than a 2600lb stripped out car.

Correct me if I'm wrong here, as far as engine breathing goes, it's easier to maintain high velocity intake flow than high volume at high RPM. Basically, it'll cost less in the end to use a set of smaller ported heads on a smaller cube engine. Cam selection is key, especially since I want to rev.

Poor comparison, but here goes. Not too long ago there was a challenge to the 4cyl turbo guys to make the most power out of 91 octane pump gas. The guys with smaller displacement had to build the engines to rev higher and lower boost to achieve the same numbers as the bigger displacement guys.
While I'm not going to be running 91oct, the same theory applies. Except in terms of boost the lower pressure = less volume and higher velocity.
EDIT: that's worded poorly, it really depends on cams and the pressure differential between the cylinder and the intake for velocity at that point, but I'm going to stop thinking before I confuse myself.

The high velocity (without boosting) is where the small displacement guys see the benefits, at least in my personal experience. I'm always open to other options, though this build will be budget minded.

ok, anyways, so basically screw the aluminum block. An iron block with LS1 pistons(stock or aftermarket) and upgraded rods is an option. Otherwise it's a 6L block and upgraded rods, possibly the 4.8L crank.

 

I've been on the phone with my credit card company's fraud division since my last post. Sheeeez, I want to beat my head against a brick wall. Ask one simple question and they ask you 20. My brain's fried.

As best I understand, the more cubes you have, the less critical small differences are at just about any power level on a normally aspirated engine. Yes port flow can be optimized for smaller cubes, but you sacrifice higher rpm power. The same heads, cam, and intake will make near the same power on a 4.8 vs a 6.0. The 6.0 will just make it at a lower rpm. When the same hp is made at a lower rpm, torque goes up. More torque is good when you're trying to accelerate a car (heavy or lite). Don't lose site of the fact that you can always detune a bigger motor for less power, but a smaller one isn't easily made stronger. If there were a big weight savings to be had going with the smaller one vs the larger, it might be different. All these iron LS motors weigh pretty much the same.

Clear as mud, huh. Hope the ******* phone doesn't ring again. If it's an 800#, I'm not answering it.

 

Just so You know Wiesco Strated making forged pistons for the 5.3L to work with stock stroke crank or stroker applications... Texas speed sales them.

http://www.texas-speed.com/shop/item...d=989&catid=38

 

I'm used to dealing with an engine that makes zero torque top end, I drive a 1.8T Audi.
Thanks again for the advice.

I saw something about the Wiesco's, I didn't look to far into them, but thanks for the link. I'm definitely interested, they sound like decent design, but I'll research them more. Anybody know more about the alloy they use? Or approx weight?

I understand the "valve pockets", but what are they referring to with "Anti Detonation grooves"?
Added bonus, they're Spiralox retained wrist pins. I hate installing C-clips/spring clips.

 

There on the board here. If you can find him, you can send them a PM...

 

Jon@texas speed...

https://ls1tech.com/forums/member.php?u=28201

 

Hey guys, I know his thread is almost a year old, but this may still help some of You. Car Craft did some pretty good testing of the 5.3L. 1st, they put an intake with a 750 Holley and got baseline #s of 335hp and 350lb/ ft. Then, a cam and valve springs for a 96hp and I think 30 more tq. Then they tested 3 different cyl heads all with the cam/spring upgrade with the best combo hitting 450 or 460hp with 396 tq. Back to the cam/spring upgrade. When they installed the cam/springs, the redline increased from 5250 or ? to 6800.
Car Craft something about the 5.3l good hp for little money is the article name.
BTW, they retained the stock compression ratio of 9.5/1 throughout their testing !

 

I know this thread is a tad old, but here's the Car Craft link:

http://www.carcraft.com/techarticles...ine/index.html

 

Dredging up a very old thread, but wanted to correct something for the uninitiated ... the LS3/L92 heads can only be used on blocks with a bore size of 4.000" or larger. This definitely leaves out the L33.