Many years ago, I used Cortina 6 cylinder engine mounts in my twin-Weber'd 144, after I got fed up breaking genuine ones.
The OD of the Cortina 6 mount is 73mm, compared to 66mm for the Volvo mount.
The distance flat to flat of the Cortina 6 mount is 38mm, compared to 40.7mm for a ProParts 140 engine mount. I used washers to shim them up that extra few mm.
I figured a Stoneage Six Ford 250 is a lot heavier than a B20 and so they should last longer than OE, which they did.
Yoshifab supplied new engine mounts with my B230 to 140 adapter brackets, but I cannot speak for their durability yet.
ETA - comparison pics, Cortina 6 mount on left of pic.