Turbo 400 to a 5.3

[Speedo]

I'm building a buggy and I have an '01 5.3 that I plan on using for power. I'm going to use a TH-400 and I have had a hard time trying to find the parts that I need to use this tranny with this engine. Bolting the tranny to the engine is not a problem, what I need to know is how to hook the engine to the TC. It is my understanding that I need to use a special flex plate and a spacer in order to do this and that the spacer is a GM part. Does anyone know what the part number is for this spacer? What about the flex plate, is this a GM part also?
Thanks,

Speedo

[Hit Man X]

Any reason you don't want a 4L60E? It's got a lower 1st gear, OD, lockup, computer set shift points, etc....

[Speedo]

I already have a turbo 400, with the doubler I don't need a lower first gear and I don't go fast enough to need OD and the 400 is easier and cheaper to maintain and its stronger. That plus the fact that I don't have a 4L60E.

Speedo

[70cst/ls1]

use the stock 5.3 flexplate. i can make the pilot for you if i still have a piece of seamless tube left. i'm a machinist, i made mine 2yr. ago. gotta go to work, i'll get back to you tonight.