EJ253 swap for EJ25D?

[98legwag]

I am doing some research for a friend who may have blown the head gaskets in his 99 GT with the ej25d. Would it be possible to swap the ej253 from an 05ish Legacy into the 99? I am thinking we would have to use the intake manifold and associated parts from the ej25d. If we did the swap would we have to use the ecu from the newer car or would the ecu from his 99 work with the ej253? Thanks for the help guys.

[86bratman]

Lots of issues running a newer engine in his car, the manifold won't swap with phase2 heads. And the 25d ecu won't properly run the 253. The best way to go about that swap would be to put the 25d heads on the 253 shortblock, using STi head gaskets. The gaskets are the problem with the 25d, they're too thick for the type of material. If you build the hybrid it'll wind up with higher compression, and gaskets that wont blow. I'm putting together one like this for my buddy's gt. It's no more complicated than an normal heads gasket job. Just use the crank timing sprocket from the 25d.

[Garrison]

+1 ^^^

EJ253 Block + EJ25D Heads

And when you're ready you can swap in sti, or 255 pistons and rods and boost that biotch!

[98legwag]

Thanks for the input. It looks like we will be pulling the engine and taking it a local Subaru shop to make sure it gets done right. This is of course after we test a few more things to make sure they are not the culprit of the overheating. He has already done the water pump, radiator, radiator hoses, and the t-stat was done about a year ago. We are going to try burping it again since the water pump and timing belt were done last weekend. Then maybe try another t-stat and move on from there.