i have the 5.3l engine in my 06 monte carlo ss. i had recently heard that the 5.7 shares the same block and engine components as the 5.7l. if this is so i could bore my engine to 5.7, change the pistons and have a 5.7l displacment on demand engine. if anyone can back this up so i could get more info on that, it would be great. i would seriously consider doing that if the block and components are the same.

 

the diffrence in the 327/350 or 5.3/5.7 is not the piston size it's the crank stroke
i never looked in to it but i can't see why it could not be done that is somthing that you would have to make more reserch on man good luck with it !!

 

What would be the problem with installing the 5.7l inplace of a 5.3l? If they share the same dimentions would one bolt up inplace of the other?

 

no because the new 5.3 has the 660 bellhousing and the other lsx have the small block bellhousing
and i was looking in to this more today and it seams that the block is about an inch shorter than other lsx blocks but the intakes can be swaped the rwd lsx have a taller intake and a bigger throttle body (not sure if it will clear the hood of a fwd car )
and i did not check if any thing elsecan interchange

 

If the 5.7l is an LS block for RWD cars, then I seriously doubt it will work in a FWD car.

 

well thats what i am saying you can't swap the motor's but maybe you can stroke the ls4 to a 5.7 displacment

 

thats is what i wanna do. i want to pull the 5.3 and bore it to the 5.7 domensions. the pistons are .3 mm larger in the 5.7. i work with a mechanic who is telling me that the cranks are the same in the 5.3 as in the 5.7. so realistically i could bore the 5.3 and end up with a 5.7 with displacment ondemand without changing anything but the pistons

 

i check it some more and it looks like the new lsx series motor are nothing like the older gen 1 i thought it was the stroke that would be diffrent but it looks like they share the same 3.622 stroke but the bore of the ls4 is 3.780 and the bore od the ls1 is 3.900
so from the 5.3 to 5.7 there is .120 diffrence i do not know how thick this blocks are but i dont think you want to bore one out that much

 

well im only here to find out more about it so any info is great. i think in the end it would be worth it to bore it the .3 or so difference. but the stroke is the same unless i get a stroker crank then id have a strokor motor

 

Finding out hos much cylinder wall space you have is the key to making this happen. If the walls are thin, doing this upgrade isn't possible.

I wander if instead of boring for larger pistons, you could swap pistons or just the head gasket and get the extra HP you're looking to achieve?

There are different thickness head gaskets out there and getting the extra (.4) HP may be as simple as doing a HG swap?