I have the following parts:
Csb 350
Edelbrock RPM heads 6089 gasket ported
Comp cam xr276HR-12 (224 int./230 exh @0.50 503 510)
HSR 24lb
Hooker 2055 magnaflow hiflow cat and 3" catback

The heads flows
100 67/58
200 130/108
300 183/144
400 226/169
500 229/175
600 232/182

Would I gain anything by using 1,6 roller rockets instead of 1.5 or does my head flow to little? any1 that has the same setup that has tested 1,5 and 1,6?

 

If you already have 1.5:1 rockers, it wouldn't be much of a gain to go to 1.6:1.

If you don't have any rockers yet, 1.6:1's wouldn't hurt you, and probably won't cost much if anything more, so go ahead.

 

I agree.

 

I have them both but my cam lifts 503, 510 with 1.5 and at that point my head flows (only) 229/175, if I use 1,6 the lift are 536, 544 and at that point my head probably flows 230/178 something so its not that much different, If my heads had flowed 240-245/180-190 I had allready installed the 1,6 but now I dont know but I hope you do, and can guide me to the right track.

 

There's more to it than that. For one, a couple of years back the world finally accepted the discovery that it is better to have relatively more agressive intale valve action than exhaust valve action, and newer cam grinds reflect this. There is a lot of merit to using 1.6:1 for the intakes and 1.5:1 for the exhausts. Also, using 1.6:1 on your intakes is more for 2 other advantages, not to get more peak lift/flow. One is that you reach the higher lifts slightly quicker, where there is more airflow, and the other is you stay there slightly longer. Your 224 duration is what the valve sees with 1.5:1, will instead be seen as 226 if you use the 1.6:1. That, plus learning you already having both sets, is why I'm now suggesting you run 1.6:1 intake and 1.5:1 exhaust.

 

I agree. Go with 1.6 on intake and 1.5 on exhaust. The split sets cost alittle more though.