Do you have a link. I have a similar issue. But mines are bent. Maybe from too much power or abuse. On one side the mount surfaces looks to have bent down a half inch. When i got the car the subfram was only held on by to bolts. So the others must have snappedLooking at mine, the 4 bushing hole diameters vary from 1 9/16" to just about 1 5/8". The distance from the rear holes to end of subframe varies between 3/4" to 13/16" . The diameter of the rubber body bushings that I'll will be installing measure 1 1/2" where they rest in the subframe holes. Kits are available to make repairs from several parts suppliers if needed.
wish i had that diagram 6 months ago... as no one down here really has any idea about Nova's... thanks Jim.. will send it to the fabricator to check measurements against that...I have to think the below info for a 1968 Chevy II Nova subframe is the same for the models from 1968-1974:
The above is from my 1968 shop manual and I have to think this info would also be in a 1973 shop manual.
Personally I would get the 2 shop manuals for the year you are working on.
On my 74 I have the old factory shop manual and the body by Fisher manual and while I have yet to look real hard, there may also be an assembly manual (which I bought as a reprint for my 68). These books or manuals are invaluable and worth the investment.