I like the LD4B better than the performer.
We took a performer off my son's 71 Valiant and replaced it with an LD4B, and it ran better and no bog/hesitation off the line.
The offy dual port dual plane intake is also good for a street driver, but restrictive over 5000 rpm, which is not a problem with a street driver. Look at this thread and see his comments in post 45 after installation. He was very happy with the results. It will also get good MPG...
http://www.forabodiesonly.com/mopar/showthread.php?t=278215
