It was a modified LS7 that came with a high-lift camshaft, newly designed cylinder heads, high-rate valve springs to prevent valve float at high rpm, a Camaro Z/28 exhaust manifold, and a wet-sump oiling system instead of the dry-sump setup of the LS7.
Needless to say, the LS 427/570, with part number 19421004, was a popular conversion among GM enthusiasts, even though Chevy never shared sales figures. Since it is an LS7 after all, the LS427/570 has also been discontinued. In case you were wondering, the part number of an LS7 is 19329246.
Both motors were cut from the portfolio in silence, and their end has been noticed by a Reddit user. From there, the folks at Road and Track reached out to Chevrolet for clarification.
Representatives of the bowtie brand replied that all current orders for the LS7 and LS427/570 will be fulfilled until the full inventory of these engines has been depleted. As R&T notes, while the LS7 was known to have a due date for the end of production, the same was not expected for its wet-sump derivative.
Chevrolet's representatives have not mentioned any successor of the LS7 or its LS427/570 sibling. It is likely that no such successor will ever come, so get one while you still can, if an LS7 was what you were looking for your next engine swap. Otherwise, you still have plenty of units to choose from. Too bad you did not get to build your own LS7, but the LS9 is still available.
Even the Cadillac Blackwing twin-turbo V8 is reportedly still available, but in limited numbers, and you can scoop one up if you can find GM Part number 12662913. Supply is extremely limited on the Blackwing motor, and these are meant to be replacement units for CT6-V cars, so make sure to leave a few in stock for Cadillac owners.