Dunno. Yeah, I also went to www.jakebrake.com
and they quickly sent me some huge files on the older Jake Brake products that needed to be modified for my application. Cummins pancake.
In the past, they actually answered my phone calls live and in person and got me an engineering question answered in about 5-6 minutes. Very professional.
If memory serves, yes, they did in fact make the Jake for the DD 2-valve head models, which is what everyone had when they came out with the Jake.
Be obsolete stuff now, but that is most of our situations. The Jake gentleman also told me they made a few for the 110 Detroit six. Hummmmm!!! Good luck.