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As a first time build, will be using RB25pistons in RB30 block, decking block to get 9.5ish to 1 with non neo head , goal is using GT3076 to get 320-350kw..

What I need to decide is what exactly needs done to the block? should NEW RB25 pistons be enough so I have a tight quiet engine and no slap..

This isn't insane power so what should I ask an engine machine shop to do with this block ( assume it is worn out) and if the tune is good can I use OEM pistons etc..??

I don't want to know about "just get a wrecker RB30 and slap a neo head on" cause I want this done tight and done once for street performance not a drifting slapper.

Edited by AngryRB
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https://www.sau.com.au/forums/topic/450575-help-needed-with-rb30-block-prep/
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I have been tracking my daily driver for three years and it just had rings, bearings and new conrod bolts. Rips will tell you that' s good for 500hp. If you want more and start reboring then you may as well go the whole hog with forged pistons, new harmonic balancer, full balancing etc. Stock rods are solid as...just need better bolts.

Is it as simple as taking the stock bolts out and putting the new arp studs-nuts in? Do you have to take bearings out etc or can everything be left in place and just the rod bolts changed?

So at this power level, using E85 and safe tune etc.. are all the stock clearances like piston clearance, ring gaps, big end bearings etc still to be followed or do these become too tight and risk the motor seizing up? for example would a 1 -1.5 thou piston clearance on an new OEM piston be safe? (manual says 0.8 - 2thou is acceptable NA)

Edited by AngryRB

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