340 buildup advice

The Comp versions of the MP cams are more mild... They're also made a lot better. So if you use the MP 284, be sure to degree it. The Comp Thumper hydraulic one I suggested is a 107 LSA and is desgined to give that idle without killing the low end too much. 340s and 318s can and do suffer from loss of low end torque when you start adding camshaft and want to keep the open chambers and pump fuel.