Looks good but I would probably go with 2 or 4oz of Chocolate malt instead of 8. Newcastle doesnt have a strong flavor and 8oz of chocolate is a lot for a brown, especially a southern brown like newkie. It also keeps the color lighter as newcastle is not a dark brown.
Might want to spring for a slightly better yeast. US-04 is only 2.70 and you only need 1 packet.
http://www.midwestsupplies.com/safale-ale-s-04-whitbread-strain-11-5-grams.html If you don't like english yeast esters US-05 would also make a nice beer with cleaner yeast and ester profile. Nothing wrong with your selected yeast I just have no experience with it.
Let us know how it turns out!
I ran this through beersmith here is the output:
BeerSmith Recipe Printout -
www.beersmith.com
Recipe: Newcastle Extract
Brewer: Scott
Asst Brewer:
Style: Southern English Brown Ale
TYPE: Extract
Taste: (35.0)
Recipe Specifications
--------------------------
Batch Size: 5.00 gal
Boil Size: 3.00 gal
Estimated OG: 1.042 SG
Estimated Color: 18.7 SRM
Estimated IBU: 24.8 IBU
Brewhouse Efficiency: - %
Boil Time: 60 Minutes
Ingredients:
------------
Amount Item Type % or IBU
2 lbs Light Dry Extract (8.0 SRM) Dry Extract 33.1 %
3 lbs 4.8 oz Amber Liquid Extract (12.5 SRM) Extract 54.5 %
8.0 oz Caramel/Crystal Malt - 60L (60.0 SRM) Grain 8.3 %
4.0 oz Chocolate Malt (450.0 SRM) Grain 4.1 %
2.00 oz Williamette [4.70%] (45 min) Hops 24.8 IBU
1.00 items Whirlfloc Tablet (Boil 15.0 min) Misc
1 Pkgs SafAle English Ale (DCL Yeast #S-04) Yeast-Ale
Mash Schedule: None
Total Grain Weight: 0.75 lb