273 Commando Rebuild Or Not?

Hang on a sec, are you sure that's a Commando short block?

That should be a 10.5 engine with domed pistons and a 248/248 cam. (I think)
My FSM does not list the LSA.
If I assume it's a 112 and in at plus 4*, then the Ica comes to 52*. When I plug that into the Wallace calculator, it spits out
191psi at 300ft elevation.
If that's true, and I do not know that it is, then your "commando" is some 45/50 psi down on pressure.
Maybe I got the wrong cam info.
For instance, if the 235hp cam was a 276/112cam, then the Ica could be 64 degrees, and the proper pressure would be 172 psi, which is still a Loooong way from 145average
But, even if it was a 9/1 engine with a 2bbl cam, the pressure should still be 161psi@ sealevel.
To get that 9/1 engine down to 145psi, with an Ica of 48*, the elevation would have to be ~3000ft.

IMO, and if it was mine; I'd be doing some more investigating.
and
If you are at 3000ft, not a chance would I rebuild that 273. You'd be way ahead with more cubes.,