I replaced the “coffee can” starter for the FE engine in my ’76 F-150 with a PMGR (Permanent Magnet Gear Reduction) starter from PowerMaster. Note the Q&A plus the reviews.



The initial install required a little grinding here.





Although this position cleared the headers, it was close. Thus, I thought that I should at least explore what it would take to clock the starter further and get a bit more clearance to insure that heat soak wouldn’t cause this starter to expire prematurely.



So here is the clockable starter. Note the awkward position of the terminals. The goal will be to clock the starter further in order to get better clearance with the headers and bring the terminals into a more convenient location. At this point there is 1-3/16” (1.1875”) between the block and the starter motor so there’s plenty of room but other parts of the block are in the way.




After a little grinding on the obvious high spots, I decided to use a little wet paint to create witness marks to guide further work.



Here is the mark that I created. Presumably, I’d need to grind from this location in a counter-clockwise direction for some as yet unknown depth and distance to get the starter closer to the block and produce the clearance I need.



However, there is a plug in the block right below where I am grinding. Extrapolating the contours of that plug suggests that there may be a point where I would intrude into an internal cavity of some sort, possibly with disastrous results.
So the question (finally) is what really lies beneath? Does whatever it is pose a threat to my efforts to clock this starter a little more?