When i put my 5.3L into my truck I used adapters from speedwaymotors in lincoln, NE. I had to put the water temp adapter in my lathe and bore the hole out for the sender as it was too small. i broke one off then had to buy another one so them i took material off the sender instead. you might look at a different sender. but i got it to work with these. hope this helps.
water temp adapter-
http://www.speedwaymotors.com/LS1-Wa...pter,8195.html
oil pressure adapter-
http://www.speedwaymotors.com/LS-Ser...ter,20928.html