I got my hands on a really old scratch project. its not .sb or .sb2, it just says .SCRATCH and i cant convert it to a sb, sb2, or sb3 file.

can anyone help???

Try importing it in a new Scratch project and seeing if it works. If not, then I'm not sure, I guess try contacting the Scratch Team.
You may be able to open the file in Scratch 1.4, then export it as an importable .sb file. Here is an online version of Scratch 1.4: http://archive.glitch.pizza/
If Scratch 1.4 doesn't work, you can select from some beta versions of Scratch 1.0 from the drop-down menu.

upload to a newer version and make a change and save it in the editor

Banana

Try to open the .scratch project in Scratch 1.0, as I seem to have some success with opening some projects from as early as the 13Oct04 build (also known as Scratch v0.2). If it fails to work, then it's likely the project is from Scratch 14Feb04, and I'm not sure if you can do anything about that.

explanation:

if <file type is (.scratch v)?::sensing> then
	open with (v1.4 v)::#AA7700
	save file as (.sb v)::#AA7700//okay your done open it with .sb3 or .sb2

oh and btw if theres a block from an earlier version that was removed it will look like one of the following depending on the version:

obsolete!::#FF0000

undefined::#FF0000