Edelbrock LD4B
I also made the change from the performer to the ld4b and noticed a performance improvement
Here is some compares between the intakes
Performer - carb height 4.63" with Port Exit .95" x 1.95"
LD4B - carb height 4.9" with Port Exit 1.05" x 1.95"
LD340 carb height 5.25" with Port Exit 1.07" and 2.16"
RPM carb height 5.35" with Port Exit 1.01" x 2.17"