It was a night of miracles here. I'm trying to get this Griffin radiator installed in my truck. They sent this fan switch along with it.
The obvious question is what's the best, easiest place to put it? I asked AI, but it doesn't know anything, so I'm posting this up for posterity.
On my truck, with a 350 small block and stock heads, there is this plug in the passenger side head, between the #6 and #8 spark plugs.
It's the obvious place to put a fan switch, but it's not that easy. The plug won't accept anything in your tool box. It's square.
5/16" square to be exact. So no, your socket extensions won't work. You'll have to run to Big Orange and scare up a length of 5/16" square bar, which is hard to find. You can grind down a 3/8" extension until it fits, but that's tedious and the heat will probably anneal your extension so it fails. Keep a tub of water nearby to quench it as you grind. By some miracle (like I said, it was a night of miracles), I had a scrap of 5/16 square bar in my deceased father's tool chest. It's been there unused for maybe 30 years until tonight.
I thought the new switch would thread in easily, but again, no. It's too small. I figured I'd have to buy a brass adapter from Summit and wait another week to get it. Except I couldn't find an adapter. Nor could I find the thread sizes I'd need. In desperation, I went to my scrap plumbing box and grabbed random bits to compare the threads against. Turns out I already had what I needed (miracle #2). The threads on the switch are 1/4" NPT. The threads in the block are 3/8" NPT. I had a galvanized bushing adapter that worked perfectly.
Here's everything you need. Even thread sealant.
And the completed install.
It took me all evening to figure that out. Hope it helps someone else.
1
