To produce reliable power, a CNC Closed Deck Modified Block is the only way to go!
An inherent issue with the EZ30 blocks are the cylinders flexing under high power levels, causing a wide range of issues. This is an issue with both the Gen 1 and Gen 2 EZ30 variety, as they both use open-deck blocks. Check out our article on deck designs If you want to know more about open, semi and closed deck block variations. The solution is a Closed Deck Block, which provides support around the top of the bore. Unfortunately, Subaru have never produced a 3L Closed Deck Block. Possum Bourne Motorsport have designed and developed a CNC program to close deck EZ30 blocks. PBMS recommend moving to a closed deck 3L if targeting in excess of 300kw/400hp at the wheels.
We have the CNC program to close deck EZ30 blocks of both the first and second generation, also refered to as EZ30D, EZ30R and H6. Please contact us if you have another block.
Note: We have also developed a 2L and 2.5L variation to suit the EJ20 and EJ25 blocks.
Please note: this is a process that can only be performed with the engine fully disassembled, so we recommend doing this at the time of an engine rebuild. The prices indicated are for the modification to the block halves only and do not include remove, stripping, cleaning, deck surfacing, assembly of the engine or any other components in the photo. PBMS takes no liability for an engine we do not inspect or build from start to finish. We recommend taking measurements and checking the block suitability prior to Close Deck Modification.
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