I would suggest that you join this Yahoo group as it is a group for those who collect and refurbish the old plastic RTF's.

http://groups.yahoo.com/group/049Collectors

You can also keep an eye on Ebay, as this kind of stuff often shows up there.

You had better be prepared for some sticker shock as all of the manufacturers/plastic planes are very highly collectable and bring prices that might make you gulp. The engines can be had for fairly reasonable prices, often.

Best of luck

Mike A.