Hey I was just double checking and maybe you guys have suggestions on the parts to go with. I have an 06 5.3 that Im turbo'ing and dropping in my 64 chevelle so Id like to upgrade the rods and pistons for more displacement and peace of mind. I was going to bore out the motor to accept stock size ls1 rods and pistons but I was told that the crankshaft in the 5.3 is different than an ls1 and the rods do not interchange between the two. Is this correct? If so is there any suggestions on compatible rods that are off the shelf parts and not something that I have to have custom made? I know that the internals can survive as is and make decent power but I like the thought of a cast 5.7 for turbo duties. BTW Im looking for forged pistons and 4130 rods not stock GM parts.

 

Yes, in certain years the crank was different and rods will not work. I think the earlier ones. You just need to check more into it.

 

If I remember correctly, my Chevy LS1/LS6 V-8 performance book mentioned that the LS1 crankshaft is actually heavier than truck cranks, but it's specially designed that way to be balanced differently. I cannot recall specifics, I'll post back later tonight if by then someone else doesn't specify.

The crank throws are the same (3.622) so you wouldn't see a performance bennefit with going to an LS1 crankshaft in a 5.3L block. If anything, just take your block and crank to a machine shop to have the block cleaned (usually sonic cleaning), magnafluxed, align honed, decks checked, bored to 99mm with plates, cam bearings installed, threads chased and flushed and cleaned again. The crank should be checked for straightness, magnafluxed, journals ground, oil holes chamfered, balanced and then cleaned. Have the same machine shop order you 4130 rods, and because they're new have them checked for straightness, balanced total mass and end-to-end, cleaned and pistons pressed on or fitted for the right 99mm bore pistons. Once the pistons and rings are at the shop ready to go then finally have the block honed to fit each specific piston in it's own bore. This would end up being the total build for a 100,000+ mile turbocharged engine, or a 150k+ motor N/A.

Usually machine shops are willing to match any aftermarket store's prices to their own when they know you'll come to them for the machine work and block prep. The amount of boost you throw at it will be determined by your availability of high grade octane. I'd think 8-10psi will be plenty for a fun little motor but if you can squeeze more out, all the power to ya. Intercooling and getting rid of that compressed air heat will be your saving grace, allowing you to run more boost on the same octane grade. I'd personally find flat top LS1 pistons with valve reliefs and then bolt on 317 heads to increase the combustion chamber size, anywhere around a static 8.7-9:1. On 10psi of boost you'll probably see in excess of 450hp, 480lb-ft of torque at the wheels. Even though you can get more on the stock crank, I still wouldn't simply because it is cast iron and mother nature is a bitch. Metal fatigue sucks with cast.

Good luck! Sounds fun!