I am working on a 360 stock pistons,i plan on useing the performer intake stock 340 exhaust manifolds holley 600,for the cam i have a chance on buying the comp cams extreme engery xe256,can i use my stock push rods and rockers,does it have the noticeable idle,or this cam pretty much a stock rv cam.74 Duster stock stall with 276 gear.what you all think good bad ugly.my second choice is the MP purple shaft P # 4452761ae would it be a better choice. T hanks .