When building a motor, cleaning the coolant passages decently requires removal of the factory freeze plugs. Reinstalling the stamped steel Dorman or OEM plugs can be a nightmare of a job. Even being very careful they are known to easily warp or damage edges of the holes. And there is nothing worse than having to pull apart a brand new build to repair a measly freeze plug.
These new billet freeze plugs eliminate all those problems. They have an aligning minor diameter to square up the plug for the initial press start. Then press in easily and firmly by simply tapping them in with a hammer. There is a shoulder on the outside edge that you can apply FIPG or silicone to to ensure it will be perfectly sealed even beyond the press seal, and the should assures it to be installed perfectly square at at the perfect depth.
Not to mention, they are threaded in the center to be easily removed for block cleaning and are totally reusable and transferable to a different block.
Machined from stainless steel, so they will never rust and give the block a great stealth look.
End users are very happy with these things and have been long overdue for the JZ platform. Your machine shop will love you for having these!
(11) 35mm freeze plugs
(2) 25mm freeze plugs