"...Do any of the piston mfg's today have anything closer to zero deck?..."
YES ! As I've posted many times, it has been said that Auto Tec will move the pin hole, at no extra cost. That way, you can get whatever pin height you need, in order to get near zero deck height, WITHOUT having to cut EXTRA material off the block.
https://shanonsengineering.com/produ...at-top-pistons
Paul Knippen here, can order Auto Tec pistons for you. Probably some others , also.
https://www.facebook.com/PaulKnippensMuscleMotors/
As has also been mentioned here many times, the machine shop should do the square-up deck cut, or whatever you wanna call it. BUT, after the decks are square with the crank CL, if you get the correct piston pin height, no more material will have to be removed from the decks, in order to achieve zero deck height.
The biggest pin height I'm aware of for a shelf 400 piston is 1.720, for the Icon brand pistons.
https://www.cnc-motorsports.com/ic89...4150-bore.html
May also be some others, including the KB "hypercast" pistons.
https://www.summitracing.com/parts/u...0/make/pontiac
The SP L2262F is 1.714.
https://www.ebay.com/itm/Speed-Pro-T...AAOSw-xVaFdO8I
I think the SP cast pistons are now 1.700.
Obviously, if you have the money for high dollar full custom pistons, you can get the pins where you want 'em. I think the Ross pistons are somewhere around $800, probably more.
https://butlerperformance.com/i-2445...tegory:1234850