306 short block is just the block no heads
306 long block is the block with heads and such
most of the chp block are stock blocks which are machined and such
dart is a stronger block alot more money tho i dont knowif dart rebuilds blocks tho.
The short block comes with the bottom end stuff (crank, pistons, rods, etc.) installed. A long block is the same as a short block plus heads, pushrods, rockers, cam (I think).
So neither is really better. Just depends on what u want. If you have good top end stuff that you plan to reuse, then you can go with the short block. If you want all new stuff, then go with the long block.
yeah short block. comes with the engine block, rods, pistons, crank, and all the other little bearings, rings, and goodies. and the long block adds the heads, valvetrain, rockers, pushrods, and basically everything from the valve covers down