can someone please help me i am building a stroker fo my nf
and i have gt40p heads my question is what extractors can i
run on this to suit different plug angles

Anny extractors to suit the E series V8's will fit, You may need to buy new plug leads with 90 degree plug boots on them. I belive you can even use the stock headers.

Stock headers won't work, I have used Pacemaker and Genie E-series extractors with my GT40P's (I have seen HM headers work too) and as said you need 90 degree spark plug leads for clearance. Replacing spark plugs is a bit difficult on a few cylinders but you can normally do it with a few different spanners/sockets or you if you can weld up a custom tool then it makes the job really easy.

BTW there are pics in my gallery of the clearance of GT40P's with Pacemakers.