Take a look at these:

https://www.amazon.com/Spectre-Perf...&hvtargid=pla-569404690319&psc=1

https://www.napaonline.com/en/p/BK_...ch_s8aAoe0EALw_wcB&gclsrc=aw.ds&

The first one was on my 261 but had been drilled out excessively to match the hole spacing and it broke. The second one is made of heavier material, is more expensive, but matched the holes in the block and I was able to reuse the hardware from the one that broke. I did have to use washers to shim the spacing on the ears as they were wider than the alternator hub. Check your measurements and spacing against these, hopefully one will work.