Hey guys. I'm just sorting out the last of my project pieces here.
 

I have an EA81 shortblock, essentially ready to go.

 

The EA71 that I bought a while back, I thought might offer the remainder of the parts I need, like heads. After taking the well worn EA71 apart tonight and attempting to test fit the heads on the EA81 block, I noticed that they don't fit. By a real quick measurement, I'd say that the outter most two head studs are about .135" further away on the EA81 than the EA71. Why is this? No idea. It amazes me how much extra time, money, and tooling, subaru wasted back in the day by making such similiar motors not compatible.

In any rate, has anyone ever successfully modified EA71 heads to fit an EA81 block? I would have just sized out the stud holes already if not for the waterjacket appearing to be different as well. I'm not even sure if the oil drain back cavern will be sealed between the head and block if I do this.

 

if someone has already had good results trying this, I'd love to know about it. If this is a fools errand than I'm on the hunt for a set of EA81 heads now as well, in case anyone reading this has a spare set.

 

As always, thanks guys.

Brian

Best to just source some EA81 heads. It would be a lot of unnecessary work (not to mention $$$$) to make use of the EA71 heads.

 

Basically the pistons are set further apart in an EA81 block, as you have discovered!

Edited September 30, 201312 yr by Leeroy

I bet if you put a wanted ad in the USMB classifieds, someone will have some good heads from a parts motor/car that they'd sell you pretty cheap. I have shipped EJ22 heads cheaply by using a large flat rate priority box per head. Came out to just over $30. to ship - which is more than many of us would pay in gas just to visit a junk yard. Not sure if EA81 heads will do the same or not, but it's food for thought.

 

Good luck!

Thanks for the heads up fellas. I just do a WTB ad for a set.

 

Brian