I have a pair of these and want to build an amp with them but I have searched on Google and can't find anything on them. Pretty sure they were used on a 7189 amp but would like to see some specs.

Lou, I don't see a TR8-3 in the listing. Most of the TR4 are from the lower power 7189, 6BQ5 and 6GW8 amplifiers.

Check out this page:

http://fmamradios.com/AmpSpecs.html

I saw that page in my search, it's a TRA 8-3 but nothing has turned up. Seems Google isn't what it used to be, too many non relevant items show up.

Sams folder for Scott 299 (6-'59) shows output transformers TRA 8-3. Horizontal (through-chassis) mount, 7K primary (probably higher) for 7189s with 360V plate, 295V screen.

That's great Tom, I have a Scott 299 schematic but not the parts list.
P.S. I found I had the Sams 445 set after all that searching I found an HH Scott Forum but it looks like it's defunct http://www.hhscott.com/cc/tube_tech_tips.htm I am thinking of using 6V6 for my amp and maybe use a board from a Dyna 70 for a driver.

That would be the first generation 299. I have one of them. Do you havea picture of the transformer?

I can post one if you need it Don.

Thanks Lou. If I trot out to the file cabinet. I can find that same Sams.

I did find photos of my 299, first generation and cropped this photo. So, the mystery is solved!

It is in fact, the earlier version of the HH Scott 299, utilizing 7189 output tubes. It is a horizontally mounted transformer.