'88 Taurus. I seem to remember a service notice about defective head bolts
in 3 liter motors that year. Don't remember if they were torque-to-yield or
not.

Also I think the proper term for your engine swap is "long block" not "short
block".

Short block: consists of block, crank, rods, pistons, rings, cam, timing
gear/chain and cover. May include oil pump and drive.

Long block: all of the above plus complete heads, pushrods, lifters and
optionally; valve covers, intake manifold, oil pan.

16 hours seems a little long, I would think 8 - 10 hours is more correct.

--
Remove "nospam" to get to me.