Sprint vs 1bbl parts differences?
 

Is the head or the crank/rods different between a Sprint motor and a 1bbl motor in '66?

Short Blocks are basically the same.

Cam, Head, Manifolds, Carb.

they did advertised that bearings were upgraded in the 4 bbl
but as Jeff says otherwise identical(also sans balancer)

Is a Sprint head or block (ZD) worth much if they need gone thru the machine shop (and possibly one sleeve)?
The mice took up temporary residence in a couple of the cylinders at some point.

Unless its for a number match scenario a block that needs sleeved is worthless IMHO.

Pretty much all modern bearing and ring offerings are superior to 1960's OE parts, so isn't a real consideration when comparing the 1bbl to 4bbl today. Pistons, crank, rods and block are the same.

Outside the obvious intake/exhaust manifolds, the cylinder heads and valve lengths are different for compression, valve springs are different for the two cams. Then the harmonic balancers are different, with a higher weight on the 4bbls.