I appreciate the interest in my secondary fuel filter adaptors, when I get them all set, I sure hope someone buys them. This is a pretty expensive proposition. I am hurrying as fast as I can on the secondary fuel filter adaptors. I will announce as soon as I can send them out. I have been running them on one of my trucks since May '08. They work perfect.
Now, on the names for the fuel filters, The first filter in a M35A1 or M35A2 system is the primary fuel filter/water separator. Since 1962 M35A1s have had that primary on the right front inner frame rail about under the generator. On ALL of my M35A2s, the primary filter is still in the same place about under the generator or alternator, depending on which one you have. If it isn't there, it may have been relocated by some previous owner/ inventor.
The double fuel filter housing on the left rear side of the Multifuel engine, is called a SECONDARY on the front half and a FINAL on the rear half. They do use identical filter elements, but the designers called one a secondary and the other a final. No matter what, these engines have a very effective filtering system. JT out