Type RA Shortblock with stock LGT Heads?

[MyMomsOutbackXT]

Hey! I currently have 200k on my 2007 Outback XT, and I think it's about time to replace the block.

 

I'm planning on putting on one of the new Subaru Type RA blocks, my question is, will the stock Ej255 LGT heads bolt right up to the EJ257 STI block? and if so, do I get the headgaskets for the EJ255 or EJ257?

 

How thick should I go on the headgaskets to fix the high compression that comes with 255 heads on 257 shortblock?

 

Thanks for any help!

Edited February 9, 2021 by MyMomsOutbackXT
added question

[Max Capacity]

https://legacygt.com/forums/showthread.php/05-lgt-5spd-ej257-type-ra-build-282192.html

 

See if that helps...

 

here's the service manual, http://people.csail.mit.edu/ilh/vacation/

 

I have a 2012 ej257 in my 05, I used ARP head studs and OEM gasket set. The Tuner mentioned there was no real difference in the numbers when he did a street tune after 500 miles on the new engine. He made a couple small adjustments but nothing critical. That was over 140,000 trouble frees ago.

Edited February 9, 2021 by Max Capacity

[B-BGTLimited]

Call me crazy, but aren't the newer D25 heads smaller CC's than the B25's meaning Subaru enlarged the piston dish to accommodate that change on the newer EJ257 blocks... which in turn when you combine a newer EJ257 D25 block with the B25 heads you end up with lower compression out of the gate?

 

Has anyone actually measured this stuff?

 

This is why I went with the short block specific for my 06 year. They are all EJ257 spec and they use the nitride cranks in all short blocks now, also the differences between previous years and the new Type RA haven't been proven to be exceedingly better IMO.

 

I'd also check your setup... my 07 IIRC is the start of the D25 heads, vs my 06 is the B25 setup. My 07 LGT Limited has the air pump system vs the catted up pipe which designates the head change.

Edited February 11, 2021 by B-BGTLimited
More detail

[DaveWaters]

This may help.

 

 

http:// https://www.flatironstuning.com/blog/what-is-the-difference-between-an-ej255-and-an-ej257

[B-BGTLimited]

This may help.

 

 

http:// https://www.flatironstuning.com/blog/what-is-the-difference-between-an-ej255-and-an-ej257

 

This is where I got my information from, and from everything I read on there my 06 block that I had, and that I got is basically a STI motor from the beginning anyways, including reusing my B25 heads. Only noted improvement on the RA blocks is the rods too, which I haven't had any issues with so I don't see the need for them at my target power level.

Edited February 11, 2021 by B-BGTLimited

[DaveWaters]

I used a new 2018 ej257 purchased from Heubergers for my 06. At the time there wasn’t that much info about the RA sb so I passed on the RA.

[dgoodhue]

If the thread starter want to keep the original compression ratio of his motor, he needs 2007-2009 LGT/OBXT motor. Using a EJ257 will increases his compression with his original D25 heads.

[MyMomsOutbackXT]

https://legacygt.com/forums/showthread.php/05-lgt-5spd-ej257-type-ra-build-282192.html

 

See if that helps...

 

here's the service manual, http://people.csail.mit.edu/ilh/vacation/

 

I have a 2012 ej257 in my 05, I used ARP head studs and OEM gasket set. The Tuner mentioned there was no real difference in the numbers when he did a street tune after 500 miles on the new engine. He made a couple small adjustments but nothing critical. That was over 140,000 trouble frees ago.

This thread was very helpful! Thank you!

[MyMomsOutbackXT]

If the thread starter want to keep the original compression ratio of his motor, he needs 2007-2009 LGT/OBXT motor. Using a EJ257 will increases his compression with his original D25 heads.

lucky for me my Outback is 2007, equipped with D25s 8)

[BoozeRS05]

Now that I'm thinking about it, I'm pretty sure I put an EJ257 in my 2008 specB with D25 heads, which by that article wasn't great. Wonder if that helped with my burnt valve in 14k miles.

[seanyb505]

Idk, I've been running an ej257 with d25 heads for about 40k miles without it going kablooey.

 

To the original ra block question, I'm not sure what the piston dish is on those. I feel like a member here bought one but it still blew up. I'd guess the piston dish would be similar to a similar year sti.