Generation IV Internal Engine - 402ci pistons

Im just looking to find the size of the piston i need to put a 402 rotating assembly into an ls2... easy noobish question so any help is appriciated

That will depend on a few thyour bore

That will depend on a few things bud, how much compression do you want to run? Are you going big cam? F/I, do you want valve reliefs, but your machinist should be able to tell you what size and what kind of piston to use.

A 402 will use 4.00 pistons and larger according to over bore. I believe they use a 1.115 compression height as well.

That will depend on a few things bud, how much compression do you want to run? Are you going big cam? F/I, do you want valve reliefs, but your machinist should be able to tell you what size and what kind of piston to use.

Re re repeat! Wake up short bus! Lol

Well im buying a new ls2 block from tsp and i went to buy the rotating assembly and the smallest piston is a 4.005 bore so i got alittle confused... im probably going with a -3cc flat top piston but will a 4.005 bore piston fit in a std bore ls2?

No. Standard bore of a ls2 is 4.000. You will need to get a standard ls2 block, take the block and pistons to machine shop and have them fit the .005 over pistons to the bore.

Do they not sell a 402 rotating assembly with a std 4'' bore piston?

They do, but it's best to have the bore honed to the pistons for a perfect fit. If you try to buy standard pistons it's a crap shoot as to how well they will fit.

Sorry my phone was acting up yesterday!

What that genius ^^^^ posted is the right way of doing it.

You need a target compression and then know your chamber cc size. My old TFS heads are at 60.5cc so I had to run a -11cc dish to get 11.3-1 on my 4.005" bore IIRC...

If I remember correctly 4.002 is standard bore for LQ4/LQ9/LS2.

No. Standard bore of a ls2 is 4.000. You will need to get a standard ls2 block, take the block and pistons to machine shop and have them fit the .005 over pistons to the bore.
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They do, but it's best to have the bore honed to the pistons for a perfect fit. If you try to buy standard pistons it's a crap shoot as to how well they will fit.
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Im just looking to find the size of the piston i need to put a 402 rotating assembly into an ls2... easy noobish question so any help is appriciated

I have a built 402ci in my 2002 Z28.. We used a 4.005 piston and honed the block to fit the pistons.