Age of Strife

My first ever Ork list (1500points), hoping to play them this evening.

1. How can I improve it
2. How can I improve it, within the confines of the available models I have at my disposal (see below).

1 Ork Warboss
Power Klaw
WarBike
attack squig
cybork body
bosspole

1 Big Mek
Power Klaw
Shoota / Skorcha Kombi Waepon
Kustom Force Field
cybork body
bosspole
'eavy armour

6 Nob Warbikers
Warbike
Cybork Bodies
Nob 1 Painboy, Doks tools, 'urty syringe
Nob 2 Power Klaw, Waaagh! Banner
Nob 3 Power Klaw, Kombi Scorcha
Nob 4 Power Klaw
Nob 5 Big Choppa
Nob 6 Slugga / Choppa

6 Nobz
Cybork Bodies
Nob 1 Painboy, Doks tools, 'urty syringe
Nob 2 Power Klaw, Waaagh! Banner
Nob 3 Power Klaw, Bosspole
Nob 4 Power Klaw
Nob 5 Big Choppa
Nob 6 Slugga / Choppa
'eavy armour

20 Ork Boyz
Nob - Power Claw, Bosspole
2 Rokkit Launcha
Shootas

20 Ork Boyz
Nob - Power Claw, Bosspole
Slugga and Choppas

20 Ork Boyz
Nob
Nob - Power Claw, Bosspole
Slugga and Choppas

Biker Warboss accompanies Nob Bikers
KFF Mek accompanies an ork slugga boy unit
2nd slugga unit stays in close promity to KFF.
Foot slogging Nobz stay close to KFF, act as counter assault
Ork Shootas sit on home objective

With the exception of the Bikes its a slow list and is low on ranged anti tank.

Additonal models I have available to use are as follows:
Weirdboy
Warboss
SAG Mek
5 Meganobz
10 Burna boys
15 Kommandos
40+ Boys
1 Trukk
1 Trukk or Looted Wagon
10 Stormboyz
2 Deffkoptas
4 Big Gunz

Do you need those nobs to be counter attack? They aren't scoring,they don't chuck out that many shots and they aren't in a battle wagon. I'd fill that gap with kan spam..but here;

Burna boyz in a looted wagon (cheaper counter attack and fast counter hordyness)
and 20 more of the Ork Boyz in shooty config led by powerclaw bosspole
Should be a straight point swap for the footslogging rear guard nobs

You gain one more scoring unit.. gain something that can suport your nob bikers when going forward against non ideal targets, gain slightly more shooty, lose a few powerclaw attacks.

That said its been ages since I played orks and taumaul et al could probably tell me why I'm wrong

20 man Boyz units can die to shooting before you get to your opponent, especially without transport in Battlewagons.
I'd suggest dropping the Foot Nobz and bulk up the Boyz to 30 strong.

It looks like your Warboss and Biker Nobz are going to have to race forward and mess your opponent about (or be a shooting magnet), otherwise it will be a shooting gallery.

In the past I've gone with 4 Mobz of 30 Boyz, 1 Mob of 20 Grots, 10 Kommandoes, Mek with KFF and a Warphead Weirdboy against a number of Space Marine players at 1500pts - they find the number of enemy hard to deal.

Watch out for Thunderfire Cannons and Flamestorm Land Raiders - they will hurt you bad - target them 1st with your Nob Bikers.

I'd suggest rokkitz on sluggas, and big shootas on shoota boyz. I just feel it meshes better - sluggas are limited to 12" shooting, so the 24" of the rokkits means they can reach out and touch something when your opponent doesn't expect it, whilst whoota boyz have great anti infantry, and the big shoota meshes with that well.

Perhaps drop a pk in the nob biker unit, and add a pair of skorcha kombi weapons?

On the big mek, taking the KFF prevents you taking a kombi weapon (although separate options, both replace the slugga, so its one or the other). PK also not really worth it, as hes an IC with S8 PK, might as well leave it on a nob, and give him a burna (gives you the option of S4 template or a PW, both of which are very tasty).