new heads or rework old ones?
 

I have a 347 stroker with holley heads.These heads were fine on my motor before I stroked it ,but I think that I might get more power from something bigger.These heads have 1.90 intake valves.Should I have them reworked with bigger valves,or should I just get new ones like the afr 185's? Is it even possible to put bigger valves in the holley's?

If it were me I would go with the AFR 185's and sell the Holleys. The AFR's would probably make substantially more power.

I agree, sell the Holleys and buy some AFR185's. The difference in price will be less than you would invest in larger valves, cutting the valve seats, blending the bowls to the seats, porting runners, etc. The Holley heads are very good heads, just a bit too small for 347 cid. You should easily be able to sell them for $750-800. Your motor will scream with a set of 185's if you have the right supporting parts (intake, cam, T.B., MAF, exhaust, etc.).