I bought a rebiult 700r4 about 3 yrs ago. Been sitting on my shop floor since then. How much fluid do I need to make sure is in it before I start the new motor? Is there anything I should look for during its first attempts at movement?

Check the dip stick , you should have at least 4-6 qts in it if its been sitting and convertor has not been drained. When you get it running , keep checking dip stick. Once satisfied, drain whats in the pan and put on a new filter and refill. Should take 3 - 4 quarts. Transmissions can collect moisture when sitting long periods of time.

700R4 transmission takes 4.7 qts. to be exact.

That does not include the convertor and all cavites. More like 10 total on a dry trans , isn't it.

It is dry now. Do I need to fill the converter and then the tranny seperately?

If the convertor has never been filled and in the car,, then its too late. If the pan is dry then add 3 or 4 quarts and turn engine over with coil wire off .. Hopefully you can get front pump moving enuff or fast enuff to pick up some of that oil. If it does and your oil level is lower now , add few more and try to start. Have rear wheels off ground on stands and let motor run with trans in gear. Keep checking fluid level. When it looks like your dip stick is near full, then you are able to put load on it and drive it .. Warm it up good and drive easy. Come back and park on level surface ,, recheck level again. Add more by the quart if necessary... Don't dump in too much at one time or over fill.

So you think my converter is hosed? Is there any way to check it?

hosed? You made me think it was empty or dry. Like I said , if you turned it upside down on its side and sucked oil out then its dry but its almost impossible by normal means to have one dry unless its got a small drain plug like the fords do. Refill it all and try it .