I am helping a friend of mine doing a upgrade on his 68 Road Runner he just purchased. Its stock except for headers and a M1 duel plane intake,Edelbrock carb. It idles smooth,not like a muscle car. Its a 4speed car,even has the Inland shifter yet. He wants a cam upgrade,poss head work to give it more of a muscle car feel,and better acceleration. He is on a budget ao he is not looking at pulling the motor,juat head work cam upgrade,something with a nice thumping idle,ideas?