Daily drivers, I have 2 that have D/D status. 1st: a 69 F-250 2WD, 390 C6, D-60 3.73 gears, stock lower end, cast flat top pistons, log ex. manifolds, D2 heads with SS valves, 2.09/1.65, hyd cam in the 270 deg range [I can't remember the exact specs as I built this engine in 1991] Stock iron "S" manifold, 600 cfm Holley and stock dist. with some tweaking of the advance curve. Runs good on Calif. 89 octane and gets 12.5-13 mpg. 2nd: 66 Fairlane GTA, 390, C6, 9" w/3.00 gears. Stock lower end, cast dish pistons, C6AE- 14 bolt heads, stock GT exhaust manifolds, SS valves 2.09/1.65, Hyd Crane cam 272/284, Edel. Streetmaster, 600 CFM, stock dist. and the usual advance tweaking, also runs good on Ca. 89 octane and gets 16-17 mpg hiway. A 3rd that is not exactly a DD anymore. 66 Galaxie, 428, C6, 9 3/8" 2.75 gear. Stock lower end, cast dish pistons. log manifolds, C1AE heads, 2.09/1.65, old 406 solid lifter cam 276/.479" Ford C7 P/I aluminum manifold, 600 Holley, stock dist. and the usual tweaking of the advance curve. Also runs ok on 89 octane with occasional 91oct. and gets 15.5-16 mpg hiway. All 3 have decent street mannners, dead nuts reliable and fuel mileage I can live with. It would be nice to get better fuel mileage, say 20 mpg but it just isn't happening with 50- 60 year old technology, big heavy cars/trucks and with an occasional heavy foot.   

I'm 65...Still have the 60 Starliner I bought in 1967 for $75.00. Turned out to be a 360hp 352. That engine is long gone as it was wore out and not running when I bought the car.

If the original fuel line and pick up is 5/16" don't waste yer time...it won't be enough fuel. 3/8" is absolute minimum. My 72 Lincoln MK IV [stock 460 w/ 4300 Autolite-5/16" line] would run out of fuel at about 85-90 mph. Driving across the Mohave desert I was just getting in the way of most of the cars and trucks on the hiway. Even got in the way of a FWD PSD Ford Super duty pulling a 28' Eliminator boat...I watched him drive off into the sunset as he passed me like I was tied to a tree. Disheartening to say the least...  

Best bet and easiest source is from a used/junk distributor. I doubt they can be bought new but ya never can tell.

Options. With your intake and cam selection you really don't a $800.00 set of pistons.

http://www.ebay.com/itm/Silv-O-Lite-Pistons-for-1966-70-Ford-428-7-0L-V8-Oversize-30-Set-Of-8-/301371681544?hash=item462b26eb08&vxp=mtr

http://www.ebay.com/itm/Ford-Mercury-428-FE-Sealed-Power-Federal-Mogul-Cast-Piston-Set-8-1966-1970-30-/171223134773?hash=item27ddb1b235&vxp=mtr

http://www.ebay.com/itm/Speed-Pro-TRW-Ford-428-Super-Cobra-Jet-Forged-Coated-Pistons-MOLY-Ring-Kit-30-/190855235688?hash=item2c6fdbc868&vxp=mtr

Thanks for the link...Just bought a set of Silvo-O-Lite 428+.030 pistons. Need to freshen up the 428 in the 66 Galaxie.

This was a first for me too...First time I ever saw a Tri-motor in flight. Nevada casino owner Bill Harrah's car [and many other things] collection in Reno had one on display. In fact it looked exactly like the one pictured above and I would bet money it is the same airplane. Not many people knew Henry was into aviation as well as cars, even experimented with all aluminum flathead engines to power small aircraft. BTW, this airshow featured rides in the Tri-motor for $75.00 per person...seem like a hellofadeal.

I have to make a correction, it is a C5AE cast block. oops
It does not look like any tool marks, as in grinding to remove it.
Hard to say what happened there, but I would say you can get find a block without a date code.

Possible is could be a service block...seen stranger things on service blocks than just no casting date.