[jmarsey]

My JBL is a solid mounted configuration using a front motor plate and special bellhousing. Tail shaft is soft mounted, of course. In my case, the engine block is a chassis stress member: adds to the torsional rigidity (stiffness) of the chassis. It’s as smooth as silk with very little vibration and not one loose bolt in 6500 miles. However, the rotating assembly was neutral-balanced, and not externally balanced as most Fords are. Other than for strictly drag racing, this is a key component and requirement for solid mounting in my opinion. The motor is much happier for it too.

If you have to ask the question, then it’s not necessary. For any kind of longevity, there’s much more required than you realize and the polyurethane mounts (great invention) are a good compromise for a street application. Hope this is helpful.