Thanks Pat. I build for a lot of guys that race the NMRO circut ranging from 505ci to 660ci. Some of the classes I must maintain a conventional style head becouse of the rules and I use Pro Topline 360's ported in house. We have them from 440cfm-460cfm and usually make between 900-1000 depending on the aplication. All so far have been single carb cast manifold. I agree on narrowing the lobe sep. With the engine and the duration being that small, it will like it tighter.