Welcome!
Tri Leva is not a Myford model type, but a means of changing speed, by using different pulley combination to effect a speed change, rather than doing so by moving the drive belt manually.
Consequently, we do not know if your machine is a ML7 or a later version.
You would ,do well to find the Serial Number, and the more expert on here may well be able to tell the model and when it was manufactured..
You might then be able to find a Tailstock if you post an ad in "Wanted"c on here, in M E W , or try Google. You might find at a machine tool dealer, or on one of the auction sites. They might even be glad to get rid of a loose item like that!
You need to specify which model it is, and to be safe, look ay the various places, Myford manual, or dealer's pictures to see the correct pattern to suit your machine. The ML 7 Tailstock is not the same as the later models .
The centre height will be the same, nominally, but the exact pattern and operation may well differ.
Hope that this is pf some help
Howard