Would like to convert my 66 belevedere 383 to a 5 speed.Im just in research and development mode right now.wonder if anyone has done this and where would be a good place to get the right stuff.

Are you afraid of cutting up the car to get the correct driveline angle and for the shifter to come thru the floor ?

I did it with a 64 Dodge 440 with a 66 and up K frame (engine moved towards back from stock). I used a lot of the information in a thread here by 446acuda for pilot bearing, etc...
http://www.moparts.org/Tech/Archive/clutch/25.html
The scattershield is a Lakewood with tapped blocks for the Tremec bolt pattern. The bearing retainer is turned down slightly to fit the Lakewood. The center of the crossmember was cut out and replaced with structural tubing welded in to clear the transmission. There are a few flanges on the transmission that were ground off- nothing of any significance. The bolt-in transmission cross member is home-made. All clutch linkage is factory.

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There are a couple of kits available to do it or you can roll your own. I put a Doug Nash in my '65 Coronet more than 20 years ago. I wouldn't do a Doug Nash these days, but back then that was all that was available.

You didn't provide enough information for anyone to really help you though. Not sure if this is a street car or a race car, not sure how much power you have, what size your budget is, etc.