Stripped my sti 3 engine to find it had heads with hydraulic tappets (wrong i know). What are the downsides of reusing these heads with the hyd tappets on an sti engine?

 

Depends on what its being used for, no major draw backs on most aplications.

 

Used as daily drive poss odd trackday with no plans to mod .

 

They are fine.

 

The Sti 2 and the early r a used the hydraulic set up, if yours was one of the first v3 it's "possibly" it had this set up from the start.

 

Did they change to shims because of the raised rev limit on the sti?

 

Yes the shim set up will be lighter and is a better design, it will ultimately be better for higher revving engines as in the later sti’s.

But if all you are planning is a good daily driver and the odd track day then I wouldn’t worry about the heads you have assuming they are in good order.