With a 2.10 low and 4.29, you will need a looser converter pump to not be as aggressive at the hit. You will also need timing manipulation. The Grid and Pro 600 is a very good and proven set up and will work fine with any data logger. With the pro 600 you ideally need to maintain above 14.5 volts to the ignition so you will need a 16v set up. A lot of people get scared of rpm but forget about the load at lower rpm's. If you have good valve train, a hemi won't care about going up to 9000. There are plenty of valve spring part numbers out there that will live for a long time at that range. Hemi's have big ports and need rpm. I don't know what kind of DA you will be racing at, but having experience with a similiar set up in a Top Sportsman car, you will want a looser converter. You will probably have to figure out how to get it slowed down to 6.70.