@garrettohio Not exactly sure what your current problem is that you're trying to solve.
Please can you be more specific with what happened and what it is you're trying to do?
Messicks shows 3 versions of the 2900
So when I look at Messicks, the injector for your engine is same as my L35 (fits 66 models)
The glow plug at Messicks shows it fits 168 models and same as my L35
PLUG,GLOW
www.messicks.com
On my D1703 engine the Injectors are
M14 Thread 1.5 Pitch
The glow plug Thread: M10 x 1.25mm
EDIT: Correction on my typo - Injector is M20 X 1.5