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2.5 block difference

Featured Replies

Is there a difference between the 97, 98, and 99 2.5 blocks? I am doing a frank and need to know what head gaskets to get. I think the block is 99 and I know the heads are 93.

edited: was thinking of wrong block

 

Not the one with flat top pistons

Edited by Fairtax4me

That combo doesn't work. 99 single cam has flat top pistons. Compression will be up near 12 and it will detonate like crazy. You need 97 to 99 DOHC pistons.

 

GD

  • Author

So with the 99 block, just use the 25d head gaskets from subaru

So with the 99 block, just use the 25d head gaskets from subaru

My compression figure IS using that gasket. Which makes it even more prone to detonation because the quench will be obscenely large. This is not a good candidate for a performance build. It will pull so much timing you won't make any power. And will likely melt a piston eventually.

 

GD

Edited by GeneralDisorder

  • Author

I'm not doing a power build. I need a motor and have the parts in my garage. So 25d gaskets?

I'm not doing a power build. I need a motor and have the parts in my garage. So 25d gaskets?

It won't be good. 11.5:1 compression will not last long. You will break and melt pistons. This IS NOT a workable combination with pump gas. It doesn't have enough cam or quench to run without hurting itself.

 

GD

  • Author

This is a 99 dual can block

  • Author

And no offense, but I didn't ask for anything more than an answer to a specific question. And the answer, i thought, would be a pretty easy yes or no.

I think you need to use newer turbo head gasket Gd talked about in other post,number ending in 604.

Dual cam block will be fine. Use the 25D gasket for 10.5 compression. Not a good gasket for longevity but will run fine.

 

GD

  • Author

Cool. Thank you. It of needs to last till summer.

And no offense, but I didn't ask for anything more than an answer to a specific question. And the answer, i thought, would be a pretty easy yes or no.

 

We glanced over your first question about the differences between 97-99 blocks, otherwise we would have gotten there quicker.  It would have been simple but it took you 4 replies to find out which block you had. A "99 block" could be two different engines - a Phase II EJ25 (99 foresters and imprezas) or a Phase I EJ25 (99 legacy or outback).  all this happens in 9 seconds in person and drags on online.

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