Weaknesses of the Ford I6 EA-EL when Turboing
This is a list of what wears heavily or what breaks in a heavily loaded(raced) N/A or turbo motor. Add to it if you know of anymore weaknesses.
Auxiliary shaft can seize : Additional oil holes can be drilled to help avoid
Auxiliary shaft gear wears : additional oil squirts in the direction of the gear reduces wear.
Stock EA pistons are weak : dont bother with EA pistons, they will break up with load and destroy the engine.
Stock EB series 2 onwards pistons are good for up to around 400 rwhp then the ringlands start breaking but piston stays intact.
Solution use ACL EA Race Series pistons which have a thicker second ringland.
Stock Valve spring bounce around 16psi. Replace with valvesprings with about 110lb seat pressure. XR6 valve springs wont do the job
Rods seem to be good to 550-600 rwhp
Head gaskets seem to go and the heads of the head bolt seem to break off : Use AU metal head gasket and AU head bolts seem to solve most of these head gasket problems but make sure bolts a really tight head corrosion damage is repaired before head goes back on. Some EA blocks need decking due to bad factory machining.
Thats all I can think of for the moment. Overall the EB onwards motors are quite strong with a few mods.