BLN215

If your bores are in good condition then you'll be using an oversize bore you dont need too and wasting perfectly good metal that could be needed down the track.You may only need a 20thou over bore so your using 2 overbores when you dont need too leaving you with less life in the engine block/sleves. But if your determined to get them go for it,just remember were only trying to help you out here.

Your choice mate but you never know the condition of your bores till its pulled down and fully inspected.

It'll depend on the condition of your bores as to how much will need to be bored/honed out of it.You'd be best to have the engine pulled down and inspected and/or machined before you shell out $1300+ for a set of pistons that you dont know if you'll need. Just the way i'd do it

O.k i'll try and bring this thread back on topic.Thanks to the guys who are genuinely trying to help me out here,there are some great points to your posts. Now a few facts about my set up,its a 355 fully built with Crankshaft rebuilders tuftrided crank/Eagle H-beams/SRP forgies with 9.2:1 comp/the blocks been decked,o-ringed and runs copper head gaskets with 4 bolt mains/heads have been slightly cleaned up with 2.02int and 1.65exh stainless valves (over the standard 1.94int and 1.6exh) and will have a custom roller cam ground to suit the turbo/manifold combo.It also runs a T56 manual box so hopefully it holds up to some of the punishment. It would have been making just over 500rwhp on 10psi with the standard intake manifold and the vortech blower and was like a stocker to drive (benifits of the larger cubic capacity and FI is it doesn't need to be wild to make huge power) so i dont think 600rwhp on 14-15psi will be much of a problem with this old dinosaur once the new cam and intake manifold are put on.

Yeah mate its got a 600x300x75 front mount already from my Vortech blower set up i sold off,would the .63's be o.k or a little restrictive on the 5.8ltr? Maybe a .82 or similar rear?

Nah its definately a 5.8ltr it was a 5.7ltr or (349.8ci) when it was a virgin bore but after the 30thou bore during the rebuild the cubic capacity increased to 355ci and 5.8ltrs

Yeah thats an LS1 forum i have a Holden 5.7ltr stroker,besides i thought you guys would have more of an idea on Turbo's being a skyline forum and all

Thanks mate real helpfull

Hey guys im new here hows it going? Anyways im about to start progress on turboing my VS GTS (355ci forged bottom end/heads/custom roller cam etc) and i was looking into running a single GT42R or a slightly smaller Precision PT74 but im almost thinking twins could be a good option. Would you guys think a pair of gt3082r's with a .68rear and the T3 style 2.5inch exhaust would be a good choice on a 5.8ltr V8?? Im looking at around 600rwhp on about 14psi with spooling starting around 2000rpm and full boost hopefully by around the 3-3500rpm mark,will these babies do the job?? Thanks in advance Nick