Rear main seal is leaking on my BBC 468 Gen IV
Went to order one at NAPA and there are three choices for the 2 piece seal.

1. A standard two piece $15.00
2. A high performance two piece that features Premium Silicone $20.00
3. A high performance two piece that features Premium Fluoroelastomer $31.00 (also says in the description, Designed for High Vacuum Appliciations)

I am not worried about the price, but I never heard of Fluoroelastomer.

Which should I use ?

Thank you

I noticed they make some good seals but I would bet the Felpro Blue viton will be just as good . Be sure to clock the seal in the block(split halves about 1/4" off center line) . Make sure you install it the right way. I hear its been done wrong.

Fluoroelastomers are just a bit better material.

Fluoroelastomers are a class of synthetic rubber which provide ... The original fluoroelastomer was a copolymer of hexafluoropropylene.

You can google it if you really want to read up on the physical properties.

alan