Hey guys,

Over the last couple of months I have been buying up some bits and pieces and doing a fair bit of reading through other peoples builds and problems etc, and just want advice on a couple of things.

The route I've chosen is a 2.5 block with 2.0 heads and will be going into my 06 wrx.

I have;

2.5 short block and crank
2.0 heads out of a Jdm ver6 sti (non-Avcs)
Darton sleeves

I will be getting pistons and rods next and wanted opinions on a couple of things

1. In dealing with compression ratios and difference in size of combustion chamber between block and heads, I am aiming to keep an 8:5:1 ratio. I have read through alot of info on nasioc but for every person that says one thing there is someone that says another.

Options;
Pistons specifically designed for the the combo (je makes a set)
Cnc Matching the combustion chamber (believe this would be the best option but an expensive exercise compared to the $4-500 available in the states, but also giving wider range of piston choice)
Increased head gasket thickness
Lastly have read no need to do anything about it.

2. Can anyone suggest a machine shop where I would enquire about close-decking my block

Thanks in advance for any help and hopefully I've given enough background.

Heinz engineering for your machine work, head torque for head work

__________________
Marti


Car: C Red S13 Silvia 2.3l 400+rwhp-SOLD
Daily ae82 4age corolla (light mods)-Sold
Daily:SWB GQ Patrol
Will be a 03-04 STI next

Keeping the 2L heads with a new 2.5L block is a common upgrade.
My opinion (caution!) is just put it on, but you must get a custom tune pref with a MoTec. Most builders will put in a slightly thicker gasket so as to maintain the compression ratio. Who is doing the work? Your builder will have an opinion and it may depend on the turbo you are using.
Machining the head to match the bore of the block is probably overkill.
If you are opening the block for sleeves and new rods then yes choose the new pistons to suit the combination.