I am wondering why anyone would install the black silicone main seals in a
Vanagon when one could install the red or even better the VITON ( green)
main seals.  They are not that much more and can take the heat alot better.
Especially if you have an aircooled vanagon.
I use VITON on my 911 and would reccomend that someone who is going to
install front or rear main seals use the VITON seals.

Malibu Tony  85' Westy    6 degrees BTDC  42 degrees full
advance..........no chip necessary