forestay length nacra 5.8

Does anyone know what the forestay length of the nacra 5.8 should be? I have a spinaker pole, no bridle and a roller. There is a almost new headsail but it is to long. Sometimes it doesn't furl properly because the headsail top touches the mast. Longer forestay?? Changing luff length??

Sounds like you have a Nacra 5.8 NA jib It will be larger than a regular nacra 5.8 jib. There will be 2 different forestays lengths the NA will be longer
A nacra 5.8 NA will have a bow foil

Hullflyer's spot on, you have a choice of buying a smaller jib or buying a bowfoil for the boat, the bow foil goes across between the bridal tangs and stops your bows pulling in. I would go the bowfoil path as the bigger jib is a big difference in performance but a small jib would be very cheap second hand if you could find one

But with a bridle I'd to give my spinaker?

There is a different spinnaker setup, where the pole attaches just under the bow foil, you have to be careful that the retrieval sock is back next to the bow foil or it becomes a crab catcher in waves, my previous 5.8 number 1626 had a chute retrieval on top of the pole where the sock went through the wire of the bow foil. The bow foil stops your bows from being pulled together and really prolongs the life of the boat