LD 340 vs Performer RPM?

Alot depends on the build and yours is mild. Ethier intake would be just fine. Though, since your starting from scratch, I'd do the RPM, air-gap if theres no need for manifold heat during the cold months.

IMO, I do believe the LD to be very good for a stroker because of the large plenum and near exact gasket size runners.
Something, the RPM is not.

Before you cut the divider down, use a spacer under the carb to simulate the extra breathing. Once the divider is gone, putting one back is not easy.

I have 2 LD-340's awaiting a good day to test them back to back. One is modified as per the MoPar book and the other is as cast. And yes I also have a RPM A-G. I have used the modified LD on a 318/360 headed engine before (4spd & 4.10) It made alot more useable power and a noticeable increase in power and RPM over the Torker II 340 I had on top. A TQ then replaced the 630 AVS. There was also a noted improvment. (And I really like the AVS)