New 440 Source 4.500" Bore RB Block

Sounds good to me. The issue of course is attention to details. They really need to get all of the details correct. Cam bore size, lifter bore size, lifter bore angles, main bore size, deck height, bolt hole placements, etc. Everything has to be spot on before the block will be a success. Small mistakes such as machining the cam bearing bores oversize will basically ruin the block so they need to have the machining centers dialed in perfect before running the production blocks.
$3500 is a decent price. Ford is now selling the SVO 460 block that has 4.500 bores and four bolt mains for $3200. They used to be $3900 but they have cut the price. Paying a little more for a Mopar block should be okay.