[Jack21]

According to some of the data in the Ford documentation, the 351W iron block weighs 195#. The aluminum SVO 351W block weighs 120#. A lot of $$$ to save 75#.

The real savings, and performance gain is in the use of aftermarket aluminum heads. An aluminum headed 351W (or 393W) is lighter than an all iron 302. This is enhanced further with aluminum intake, aluminum water pump, and aluminum steering rack (Flaming River manual, or '79-up OEM Ford power) instead of iron MII. So, you're still maintaining your ~50/50 weight distribution.

The coil overs allow you to easily adjust front ride height that you can't do with the OEM spring setup.

Trying to move the engine forward or back, at least with a CR, is an exercise in futility. Put the battery in the trunk instead.

Remember also, that the 351W mounts 3/4" - 1" lower than the 302. Use 351W specific motor mounts. And, you have to drop the trans a like amount or the engine will tilt forward, and the sidepipes will not be parallel to the body.