90 suburban 3/4 ton 4x4 5.3 swap. Couple questions.

So i cant seem to find the answer to a couple little questions i have on my swap. Im running a th400 trans and a np241 transfercase. The truck is an electric speedo from the factory. I would like to use that signal for the computer to listen to a vss. My question is, how do i then get the trucks speedo to work again? Does the 5.3 computer have a speedo output that will go right to the guage? Truthfully i have no idea how it works on the TBI setup, but i think the computer gets the signal and then spits it out to the guage. Is it just a matter of tapping in the wires off the new ecm to the wires that go to the speedo? Also, will the stock 90 temp gauge read the three wire temp sending unit mentioned in the part numbers for lsx swap sticky? Thanks!

Im in the info collecting phase of my swap and should be picking up my motor the end of next week! Trying to be as cought up as i can be! I'll turn this into my build thread which will mirror my build thread here,

http://coloradok5.com/forums/showthread.php?t=291277

Check out lt1swap.com He has lots of good info, including pcm pinouts. It is pin 50 on the red pcm connector 99-02. 03-07 pin 50 on the green connector.