Technical SUN Tach Identification Help Needed

Need some help here. I've searched everywhere but can't find this specific SUN tac even though I've got the part number and all. Any thoughts. It's about 3" in diameter and is designed to be installed in a panel vs. column or dash mount

 

The box indicates 8000 rpm but tach is only 6000 rpm? There were panel mounted tach’s. Boat maybe?

Maybe this will be of help. Does not hurt to call number below. https://www.bobsspeedometer.com/in-the-shop/sun-tach-rebuild/

 

I have a similar one . Kind of looks like a miniture Super Tach. Anyway, it was originally sold for snowmobiles. It's 4 cyl only and does not use a trnsmitter. The tune up shop I worked at was a Sun dealer.

 

The one I have isa ST 502. It is an 8000 rpm and has an approximatly 3/4 scale. 0 is at 6 o'clock and the 8000 is about 3.

 

Here's one that looks just like it on Ebay for $75.

https://www.ebay.com/itm/2672002105...ciLPj0DlKSHEdut9Pw2Eb2nwQ=|tkp:Bk9SR4bL8NTRZQ