A guy on the SVX board is trying to ID this...

 

 

There are more pics here;

http://www.subaru-svx.net/forum/showthread.php?t=58517

Certainly it is from an EA63 or EA71. This is obvious from the way the air cleaner assembly mounts to the carbs (On the EA81 there is a stud in the middle of the carbs the air cleaner bolts to...). Therefore the manifold will be too short for an EA81...

 

To tell if it is from a EA63 (1400) or EA71 (1600) measure the heater outlet pipe (I suppose it is the outlet?) on the manifold (down near the mounting holes in the picture) . An EA63 manifold will have a 1/2 inch outlet while the EA71 will be larger at 5/8 inch.

Certainly it is from an EA63 or EA71. This is obvious from the way the air cleaner assembly mounts to the carbs (On the EA81 there is a stud in the middle of the carbs the air cleaner bolts to...). Therefore the manifold will be too short for an EA81...

 

To tell if it is from a EA63 (1400) or EA71 (1600) measure the heater outlet pipe (I suppose it is the outlet?) on the manifold (down near the mounting holes in the picture) . An EA63 manifold will have a 1/2 inch outlet while the EA71 will be larger at 5/8 inch.

 

 

the little nipple bit on the bottom left of the picture ?

in pretty sure its 1/2"

would it be worth much ?

They could always mod an EA81 manifold with sections of that one with the aid of a tig welder and a die grinder to obtain the correct length,cutting just outside the carb mountings would allow access to clean up the welds after and then play with jets the performance gains would be worth it.

Just make sure when welding have it mounted on an old ebgine to keep it square.