This guy?
Amazon.com: Stant 13358 Thermostat - 180 Degrees Fahrenheit: Automotive

 

So where exactly is this bleed hole supposed to go? The link pic looks like the surface is solid on this Chevy t-stat. And this would work in the 3.9 and 4.0 V8s?

 

got this today

 

yea, its solid. you drill a small hole at the top.

yes, stant 45358 is the more "HD" version

 

Okay, so in looking at the pic of this t-stat (13358) again, there are "bumps" at three and 9 o-clock, so this 1/8 hole would be drilled at 12 o'clock? In the same relative position as those "bumps", more towards the outer edge, inner edge, or?

 

My truck always runs 185 until it got super hot here recently with the stant. Might be time for my spare radiator.

 

You drill the hole in the wide flange part, when you place it in the engine the hole is positioned at 12

 

I used the Stant Superstat part # 45858 purchased at Advance Auto. It's a 180* with the bleeder hole.

 

So the only difference between the two t-stats is one has the bleeder hole and the other doesn't, and maybe price? If so, sounds like getting the one that already has the bleeder hole would be the preferred way to go. That way I wouldn't chinger up the mounting surface trying to drill a 1/8th hole.

It's interesting in that Amazon.com says this t-stat won't fit my D1. When I click on replacement t-stats that DO fit, there's a whole page of them, to include AC Delco, Motorad, and a few others, but neither of these Stant ones (45858 or 13358).

But I will defer to the wisdom and experience of the forum, and use one of these Stant t-stats next time around!

 

I picked up a cheap Moto-rad 180 fail safe t-stat. Seems to be working great.