a 426 smallblock package will last, no problem. especially with light pistons and rods.
The rod/stroke ratio is still better than a stock chevy 400 AND the block is ~.6" taller.
So a longer rod can be used. the chevy 400's used 5.565" rods. A ratio of 1.48 and a 9.025 tall block. The taller mopar block helps cause you can use a longer rod. this helps with wear. Moly rings, good oil and lower rpm's and light reciprocating parts mean it will last. Just got to keep the fuel from washing the cylinders (accurate A/F ratio's)
I am going to build one myself. I dont kow why this subject gets folks all riled up. oh well.