blander66

iTrader: (2)

i am looking to bore my 5.3 out to LS! specs at 99mm but i am having a hard time finding pistion at the stock ls1 bore they are all a little over sized around 99.187 mm is it safe to take a 5.3 block the extra .187 mm over 99mm ?

5.3LJimmy

iTrader: (10)

Yes you can safely bore the 5.3 to 3.905".

1FastBrick

iTrader: (16)

You need to have it sonic checked to see if it will go over that far. Not all Block castings are equal and a few have actually been to thin and ended up in the scrap pile.

1FastBrick

iTrader: (16)

FWIW Weisco now makes Forged slugs for 5.3L bores

02BLACKTAWS6

Isn't the 5.3 an iron block? Curious... not positive.

1FastBrick

iTrader: (16)

yes unless you have an L33 aluminum 5.3 or even the Fwd 5.3L not sure what the code is for that...

99LsSilverado

iTrader: (3)

I am doing the same thing had an iron block 5.3 bored out to ls1 specs. If you want to go with the stock size 99mm (3.898") you can get those pistons from Mahle if you go to jegs.com and look for part number 644-LS1340898F01 it comes with pistons rings pins/clips. That is where I got mine from.

fastazzls1

ls4 its wat comes in ss impala its shorter due to being transversely mounted but still a 5.3 same bore and stroke and nice picture of the 55 thats my dads friends 55 bertha built by monty bernie

1FastBrick

iTrader: (16)

Yup thats his car, pomona 05 supper chevy meet. Also know him from PSCA. Havent been out to see his new car yet.

On the LS4 FWD application, I belive it is the crank that has a shorter snout and a balancer that hugs the block.

evangto87

iTrader: (6)

similar question... i just recently cracked a sleeve on my motor.. can get a 5.3 iron block really cheap. Looking to have it bored to diamond 3.905 piston specs. Seems the concensus is that this can be done. Correct?