THe guys at my Big Block Ford site turned me onto this extremely nice tester. The owner told me they are working on a second version to change the angle of the handle that should help it clear marine headers.

http://www.buxtonengineering.com/vst_600.htm

I am not sure just how much change he is planning to make but if there are any other interested parties out there, it may behoove you to contact them through their website to give input. I'd hate to buy such a nice piece only to cut and weld to clear my Stellings. My suggestion was to make a longer connecting rod from the main handle to the base under the gauge.