I recently got some Ea81 heads off of an 87 brat in the JY.I have the heads disassembled to do some porting on them.The question I have is: When is it a good idea to change the valve guides out for new ones?The brat I got these heads off of had 223,000miles.I am going to replace the seals so I thought maybe it would be a good idea to replace the guides.Also does anyone know why there is only the seals on the V guides on the intake valves?That also had me wondering.Thanks in advance.

They may or may not need replacing - my ea81t that was in otherwise absolutely shocking condition didn't need them - still well within spec. I'd get them measured before making a decision, or you could just replace them anyway if you can't be bothered measuring.

 

Some early ea81s had seals on the exhaust valves too (i think) - perhaps the exhaust valves get too hot and ruin the seals quickly??

Subarus are very easy on guides. I'd measure them, but they're probably fine. You can also check by inserting the valve most of the way and trying to rattle it back and fourth. It should move a little, but not very much.