I know what everybody's gonna say just get a ls1 block. Budget dosnt permit and there are no ls1 blocks to be had were I live with out getting on eBay. I already have a 5.3 so im gonna get it bored. My question is will I have to use a ls1 crank I know the 5.3 and 5.7 have the same stroke but they have diffrent weights can i use the 5.3 crank and get it balanced? Has anybody just bored a 5.3 used ls1 pistons and just used 5.3 rods and crank? The blocks gotta be bored either Way it's a cast iron block I figured if I'm gonna bore it I'm gonna just get it punched out to a 5.7

 

Did this with my aluminum one. everything you said is fine. balance it if you want. doesn't matter unless you're planning some extreme rpms.

 

Agree to an extent. The 5.3 crank is the same as the LS1 except the LS1 crank is gun drilled, so I'm not sure what you mean by weighing more, it should be damn near the same. The 5.3 crank is designed for 5.3 pistons, so you should balance the rotating assembly. Any time you do a rebuild you should really balance the rotating assembly

 

knew someone was going to say that. and yes. but yes again, you can swap them. BTW. the 5.3 pistons and rods are far superior to the LS1 ****. (at least by looks.. I did not do an in depth metalurgy check, but its painfully obvious) Check this out. Full floating too. ridiculous. I hated to swap it out. 5.3 on the left.

 

the 5.3 rods are full floating? im was kinda surprised how beefy the 5.3 rods looked i still might get new rods only on account of getting new rods bolts and having them re sized. i can probably find a set of rods for a few bucks more.... whats the wall thickness on a average 5.3 block standard bore? i plan on doing a little hp even if for no more reason then just to know i have it all balanced id like to find a shop to balance it all.... im looking forward to getting my motor togeather and seeing what numbers i can squeeze out.... do 5.7 ls1s have bigger injectors then the 5.3 vortech motors?

 

not sure if it matters or not but my 5.3 is out of a 99 extended cab truck.

 

Im pretty sure there's a difference in years. These came out of a 2005 trailblazer SS.

 

anybody know how much hp peoples ran with a 5.3 bored to a 5.7? a few places iv read said people use the 5.3 blocks and bore them because there stronger then the aluminum blocks..... im gonna take it to the machine shop tomorrow and see what they say about it. whats the average cost to get a engine bored?

 

GM High-Tech just did a 5.3 iron block bored to a 5.7 (3.902) bore and make over 720 hp & 770ft-lbs with it.

 

can you bore an aluminum 5.3 to get a larger bore like the 5.7 fbody engines

 

Yes, that year is 21.7lb/hr injectors..the LS1's are 26 or 28lb/hr depending on the year.
No, me personally I would go .010" over at most on an aluminum engine.

 

I am in the midst of doing what you are contemplating. I have a couple gen 3 5.3l's (LM7 Iron Block). There isnt enough meat on the sleaves to bore an alum block out to LS1 specs. There is also a difference in the crankshaft on the truck 5.3L vs the ls1 in that the truck accesories have to be used when using the truck crank. The difference is in the distance from the front of the harmonic balancer mounting point of the crank. Then the crankshaft is also balanced for lighter 5.3L pistons. I would think that using the 5.7L pistons with a 5.3l crank would cause the engine to self destruct from being severely out of balance. Its only around $200 for a LS6 rebuilt corvette crank. Then you will also have to take into account the 5.3L heads and what kind of CR you will yield and the valves are smaller than the LS1 unless you were lucky enough to get factory 799/243 heads on your engine which will have the bigger valves.
The reason the 2005 5.3L pistons are floating is because the Gen 4 engines have floating rods and the gen 3 do not (pressed). The 5.3L and 5.7L rods are same part number when in the same generation.

Machine work typically is around $20 per hole for boring but some machine shops may charge more since you are removing quite a bit of metal when going from 5.3L to 5.7L.

Im doing it .....just because i can.....and 5.3L are so cheap and can be had everywhere. Picked up 2 of them for $250 each complete.

Im going with the LS6 intake, 799 heads (picked up a brand new set for $400) and flat top pistons with coated skirts ($315). I dont need forged since i wont be running boost.

Its an engine rebuild and bore so it wont be ridiculously cheap like rebuilding a gen 1 350, but it will be strong if done right and you will always have a "spare" block waiting in your nearest junkyard.

I say 5.3L LM7's are like X wifes....everyone should have atleast 3 in the garage...or behind the garage.

 

Just dropped the block off at the machine shop new cam bearings bored baked and tumbled and magna flux for 340 then another 2 for balancing. Anybody got s set of forged ls1 pistons for sale?

 

Why do you want forged? Are you going to run any boost?

 

Let me know how it turns out. I have been disassembling a 5.3 block this past weekend to take and have it bored out to a 3.905 to make a forged 347

 

In my opinion all this machine work I'm getting done would be a waste of money if I didn't put forged pistons in it. Shell probally see more spray then boost but I'll eventually put a turbo on it. As soon as I find pistons and rods they can do the final boring and pick up my block

 

ugh, the internets....

Well. Then you better go tell my 5.3 liter L33 (aluminum HO block) That's bored out to 3.878 that it can't do that! lol. It Can and IS done. You guys were listening to too much internet banter, and now vomiting it out as fact to this poor guy. I have the 5.3. I bored it, and it's great. I didn't have to buy 243/799 heads because it came with the motor. (smaller valves and lesser cam than a Z06) Paid $705 for the motor complete. 60K mile motor. Looked more like 30K miles. So.. For $250 in machining, A very nice set of very lightly used LS6 rods and Pistons ($160) new bearings and piston rings. $230. $200 crank assembly balance and then, I have a fully rebuilt bottom end to LS6 specs.. (add rebuild gasket bolt kit for $160)
Total cost (If I were to leave it at that) is $1705 for a Very nice rebuilt 5.7 liter That's pretty identical to a Z06 bottom end. And will make very nice wheel horsepower. reliably for a very long time.


That said. the 5.3 HO L33 is actually an outstanding platform for boost in its stock form.

 

Well you mustve got something special there with some thick *** steel sleves..it's not internet banter, I'll post a pic of the LS1 I have sitting in the garage, I assure you there isnt much sleve there to bore..lol

 

Did u use the stock 5.3 crank and just get it balanced? Are z06 pistons forged?

 

i was looking at getting an lm4 engine at the local yard. so can it be taken to a 5.7?