I believe the old pumped version is already PDP ported. So sending it to Clarence Lee would get you nothing but a bored out and loud muffler, oh and blueprinting. You may have a leaky diaphram from age hardening. I doubt you will find a replacement buy you can check out the K&B site. Don't know the link but
http://www.mecoa.com will have a link. If not maybe you can buy a plain backplate from them, a new external Perry Pump, and you should have the power this engine originally had. Plus you can use the pump for future projects on differant engines as well.