Since all of the links are broken, does anybody have a copy of the Screamer manual they'd be willing to share? The rest are available at www.sirenmanuals.com if I recall correctly.

The main difference between them as far as I can tell is the rotor size. The "S-2" was listed in a FEMA technical review as being 101 db @ 100'. The S-5 is 105, the S-7.5 (Which was also available in 9 port, not just 8) is 108, and the S-10 is 112.

I've confirmed it is a 2790. Here is a photo:
https://photos.app.goo.gl/DJXtcJdqt5hS1VKs7

Your Thunderbolt 1000 appears to be a quite rare "jail bar" Tbolt. These were produced for a very short time, so my guess would be early to mid 50s. On a side note, may I ask what you paid for it?

It is nearly impossible to get a fair cost, because there aren't that many, it doesn't have the Hemi, it is likely not in perfect condition, and even if there were others exactly like it, you're not likely to find them and ask what they paid. Way back during production, they cost $5500 new, (~ $43,0...

Upon disassembly, the horns could be set in any direction.

Sorry about posting the same picture, I meant them to be different.

This topic is devoted to those sick sirens out there.

It appears to me to either be a model 5/7 or a model 3.