Ask around with some of the local racers and engine builders about that dyno shop before deciding
I like to see indidual EGT probes and read outs on each header pipe and dual O2 sensors, one on each header collector to help tune the motor, that is IF your planning on wanting to tune it on the dyno
Do you know if when they make a dyno pull do they record the data pulling from down low on the RPM to the upper RPM or do they start recording it at WOT and pull the motor down the lowest RPM you want to see data on? It makes a difference
What brand and how old is the dyno and software?
Ask them if your motor will be the first BB Mopar they had on thier dyno
If so make sure the prices quoted are firm and not by the hours of total time including mounting, running and dismounting it
A good dyno can really save you some tuning time, a bad one can kill the motor quickly
Bottom line is I never rely on the final tune up on the dyno once the motor is in the car, I finish the tune up in the car based off of of the spark plugs and time slips and or the wide ban in the car
Let us know what you decide and do