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Ok , so from reading this im guess a rb30(n/a) bottom end will not just bolt straight in....

i have a rb25det (automatic) in a R33 gtst i dont wanna change driveline .

Will my box fit? will the engine mounts match ? its a great thread but im just looking to bolt on the rb30 bottom end without changing pistons and grinding galleries? is this possible???

thanks in advance

Edited by Veilside-SaU

Im pretty sure all spigot bearings are the same. rb30, 25, 20 and 26 identical. Ask for an rb30 spigot bearing...chances of finding that are probably better as its from an australian car...some automotive stores dont know any better. Ask for a 26 and the list will only say rb30....and the pimple faced kid behind the counter will say 'sorry sir the computer only lists one for an rb30 out of a vl commondore, cant help you...'

Idiots...annoying sometimes.

RE: Belt sizes.

Just been looking on dayco.com.au, heaps of belt options.

94843: 153 teeth, STP8M pitch, 25mm wide (not that it needs to get any longer)

94407: 152 teeth, STP8M pitch, 25mm wide

94604: 151 teeth, STP8M pitch, 25mm wide

94777: 150 teeth, STP8M pitch, 23mm wide (this belt is equiv to gates t306,150 teeth)

94830: 149 teeth, STP8M pitch, 25mm wide (pretty much spot on for low low setup)

94109: 148 teeth, STP8M pitch, 25mm wide

94652: 147 teeth, STP8M pitch, 25mm wide (getting a bit short....)

Hope this helps a few people, Im gonna work out the best one for the low low tensioner setup for mine, will post up results.

Edited by Godzilla33

hi guys i have these pistons

AP340754 Arias - Arias Forged Pistons Rb30 Non-turbo 86.5mm Bore Supplied With Rings

how good are they for this conversion???

what comp ration would it give with 1.5mm head gasket and rb25 vvt head?? and the block has been faced if that makes a big diff (not sure how much tho)

the non-turbo pistons are better for this conversion yee? or is that just the standard non-turbo pistons which are better??

whats teh differance in strength between the turbo and non turbo pistons?

Hey Scooby,

yeah, pitch is the same as std RB30 belt, Im 99% gonna use the 149 tooth option with the low low 2 tensioner setup. Gives that bit more clearance between tensioners. My local Repco doesnt stock dayco, gonna try get one tomorrow elsewhere.

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