I am not familiar with "Marks", is this an aftermarket regulator? You said adjustable, so I assume its not a stock bosch. You dont have a digital camera, but can you search the web and find a picture of one like yours?
I have not heard of a Marks either, this is just what the previous owner told me. It is exaclty like the regulator on my 86 so I assume it's a fairly common one. I'll do some research and see what I can find! Best way to describe it is that it's all black and the vac port is on the side towards the top. ------Jeremy
If the upper half looks like a pipe cap then it is most likely one made by Mark Martone - he made them in his garage and sold them for several years, mostly through the old gnttype list. Always had good reviews. I recommended them to several friends and would run one if I needed a reg.
Thats what it is. The previous owner of my car got all of his parts and did all of his research on gnttype. Must be a good one because I've had them on 2 of the cars I have bought so far! -----Jeremy
