Originally Posted by KCS

An LS1 isn't supposed to go more than .010" over (yet some have...) but the aluminum 5.3L blocks can go out to 3.905" as well.

Originally Posted by remauto1187

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.

I'm 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.

I'm 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.

Originally Posted by chrisfrost

What You're doing "going" to LS1 specs with an aluminum 5.3L is replacing the sleeves with larger 1's .
The LS1 and LM7 cranks are the same part # just different weight of the bob-weights . So the snouts are the same , when You want to put LS1 or LS6 accessories on a LM7 You need to not only change the brackets and the water pump but the pulley/damper as well .
Speed-Pro 4.8L cast hypereutectic flat-top skirt coated pistons are $180 a set at Sumitt which as I'm sure You know will work as 5.3L replacements . If it were Me I would look for a deal on an 6.0L truck engine and build it up a little

Originally Posted by lowrolr

I am doing the popular 53 to 57 bore but my question is about the crank. I need to use the car accesory brackets cause it is going into a s series blazer. So what i need to know is can i run a ls1 crank in my gen4 53 block without any issues

Originally Posted by jays78

I have a ls1 with a hole in the block, rod poked through on startup, all other internals are good.

I can pick up a 5.3 for 300 bucks, my question is can I use all of the ls1 parts in a bored out 5.3?

And can I use one of the rods from the 5.3?

Originally Posted by kossuth

Maybe...... It depends o. A few factors to be honest. Gotta have the block sonic checked to ensure the block is actually thick enough. If it is thick enough I would reuse all the rods from the 5.3 vs piecing in one from a set of mismatched rods. It might be hard to get balanced if you just mix and match rods particularly if you get a newer 5.3 with ls2 rods. Food for thought.

Originally Posted by bradw18

if i knew now what i knew then i would of bought a 6.0 block

Originally Posted by bradw18

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?

Originally Posted by dawgs74

is that aluminum or iron.....5.3 to 5.7 bore?