So I have some questions my blocks at themachine shop

[e30m20TurbO7]

Soo I'm going to deck my block to drop the Compression ratio
It has all stock b25 internals
I'm not sure how much I should deck it
And I'm of course going turbo
Any advice
And should I not even deck it

[$hane]

I wouldnt take much of you plan to turbo it. Just ask him to take as little as it needs to clean up.

[jlevie]

Decking the block (or surfacing the head) raises compression ratio, which is not what you want if going to FI.

How much you can take off the block depends on how much has been, or will be, taken off the head. It looks to me like you should be able to get away with 0.010" off the block if the head is at minimum height. If the engine will get FI, I'd have a minimum cut made just to get the block dead flat.

[BavBeater85]

yeah, m20b25 actually has right about the right compression ratio at 8.8:1...I wouldnt mess with it

[e30m20TurbO7]

Block it gonna be dead flat of course
He dd t suggest to deck it but just to machine and make it flat
Thanks for your advice
My head has been machined by a previous machine shop