These two housings came from my "streetport" tii engine i am currently rebuilding.
What kind are they?

looks to me like s5 tii on left and s4 na on right?

Plug view

Top view

Inside plug view


as i was cleaning i had noticed that the spark plug gaps are different.

the car is a 1987 tii however the motor was rebuilt for street/track purposes in the early 2000s by a less than reputable shop,

Can anybody tell me for sure what housings i have. I know not to mis match incorrect housings so ill have to ditch the bad one anyhow.

 

I think you're correct about the one on the left being a S5. It has the boss for the knock sensor in it. Right above the trailing plug.

 

Definitely S5/S4 as the >'89 had the plugs further apart.