is the aluminum 5.3 interchangeable with the iron block?

phatride · August 6, 2013

hi guys ive been lurking for a while but this is my first post.

i work for an independent shop and i have an opportunity to buy an 08 silverado that has the aluminum 5.3. the motor is shot. i already put new main and rod bearings at the owners request but to no avail it needs a motor.

my question is can I swap an iron 5.3 in its place? The aluminum motors are quite pricey and the iron motors seem to be about half the price used.

ive worked on enough of these truck to be confident the mounts are all the same, but im worried about small difference like cmp and ckp sensor locations and small unforseen things.

does anyone have any first hand experience with this swap? thanks!

Badass69 · August 6, 2013

LY5 will drop right in the place of a LH6 or LC9. Just get a pre 2010 one so they don't have vvt. And of course you need a gen iv engine not a gen III from the previous gen trucks.

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phatride · August 6, 2013

Okay sweet. Any specific model the ly5 came in? Do you happen to know the vin code?

Badass69 · August 6, 2013

J is an LY5. The LMG (code 0) is an iron block too and the only difference worth noting is flex fuel compatibility so bigger injectors. Reusing your current intake manifold would negate any of that. Performance wise whether iron or aluminum they all use the same pistons, heads and cam so you won't tell any difference.

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phatride · August 6, 2013

That's what I was thinking. Thank you very much!!!

nickvrebel · August 7, 2013

it will swap long block for long block....

you will want to use the original fuel injectors/ rails for the truck. This will avert any issues with the possibility of a Flex Fuel/ non-Flex Fuel mix up.

My truck has a 5.3L Aluminum block and is NOT Flex Fuel compatible, I know in the past there was different size fuel injectors used for Flex Fuel (larger), they can be made to work, but that would require a custom computer flash and it's just not worth the trouble.