Depends on how much casting flash there is along the underside of the lifter bore area. Mine and most other posters over the years (here on Moparts and other forums) did not require any block machining...

Yep, it's easier to install with the block upside down and the crank removed. A bit tricky with the engine in the car though Somebody else on here did the same "half-pipe" trick inserted the length of the cam tunnel, but he used a magnet on a flexible stick that made it easier to drag the lifters to the proper bore.

Don't forget it's quite a bit cheaper than buying a roller cam and a good set of roller lifters, too. My 1982 DC books claim "very close to roller cam performance at about half the cost".

I'm set up for about 140# on the seat and 430# at full lift (.654 gross with the 1.5 rockers). That shouldn't be hard on parts and I'm not going to turn 7000+ anyway.