Here's a new Core Plug Set for the following 4 cylinder models models from Austin -

AUSTIN

Austin Allegro  (1000cc) (1971- 83)

(** 1.0 Litre Only **)
 

These plugs are pressed into the engine block to fill up holes left when manufacturing the engine.

After a long time they rust and you start to leak water, if you keep your car full of Anti-Freeze this helps protect them against rust.

It's very easy to change these, to remove the old ones you knock a sharp scredriver through the old core plug and lever it out. You then press the new core plug into the block, put a flat bit of wood over if and hit it home! (You'll need to drain the water out of the engine / radiator first!).