[HO455]

I am wondering what has gone wrong with your current set up that is forcing you to make a change. No mass produced distributor is going to drop in and work correctly especially if you have made other changes to the vehicle. The stock unit was a compromise made by GM to balance driveability, warranty issues and COST. Truly the only way you will have a distributor that makes engine run at its best is to have it curved by someone who understands how it is supposed to work and is willing to spend the time to get it right. Most all of your choices are involving a compromise of some sort. Remember that there are many good aftermarket units out there that have quality engineering and good parts but are assembled by minimum wage workers in foreign countries who will never see you. I won't go into all of them but I highly recommend that you tear your's down to double check the assembly process prior to installation. If your planning on long trips or offloading look at the cost of carrying spares if the unit will allow field repairs. HEI's are work well, but are difficult to curve properly as they were designed for low compression smog compliance, plus when they fail it is usually without notice and it is difficult to do field repairs. Pertronix units work well if installed correctly (once again good idea but victim on cheap manufacturing) and if you distributor is worn out or has a bent shaft it won't fix that. The plus is you can for most vehicles switch back to points in the field and get home if it fails. For GM vehicles I use an old 50's or early 60's cast iron unit with a Pertronix unit. The old distributors have much larger bearings, the machining is better and the cast housing is less likely to warp. The ease that the pre-HEI units can be recurved if I change something on the truck (cam, convertor,gears,etc) makes things easier in the long run. This with the peace of mind that a spare set points in the glove box is what makes the choice for me.
Good luck.