Do a search, this one's been discussed a dozen times and my position hasn't changed.

As for the dual plane vs single, it's more about if you want maximum torque....lower stall and taller gears and higher curb weights favor the a dual plane RPM over the Holley Street Dominator...but not by much.

The Performer RPM is the Least dependent on the combo specifics, that means it will work well on a stock 440 and it'll work on a 600+ HP dual purpose car...or even a motor home.

I like the SD or the Indy dual plane better than the RPM...but not out of the box, they both need a bit of porting and they like a bit more "optimized" stall and gear.

If you're going to stroke it in the future, the Indy dual ported to MW will easily support 650-700hp, so there's more Upside if you have plans down the road.