Comp cams xe268h for 318

IDK, it seems like A good start here. Missing the compression ratio and actual head work & specs....

Yes, the split duration cam has an edge on a stock head. The porting work would have to show a good balance between intake and exhaust ports to consider a single pattern cam. Generally a slightly off balance in the exhaust flavor would allow a single pattern cam into the picture. Otherwise, most times, not every time, a dual pattern shows it self better.