Issues with 360 engine mounts

George Jets, please dont confuse the guy. the 273, 318, 340, 360 V8s all fit the same V8 K frame from 67-72. The passenger side mount that bolts to the block is the same for all 4 engines into the 67-72 K frame,

the drivers side mount is what's specific. A 273 318 Drivers side mount will work on a 340 360 if you use a longer bolt and a spacer between the aft ear and bracket. Pic shown is a spool mount, but idea is the same with the flat mounts.

View attachment 1715717811
how big of a spacer does it take? Or what should I be looking for to tell if I need more or less of a spacer? Just the engine level?