oh man i hope to god im wrong and the other guy too. your timing could be off. and if it is bad enough that "clanking noise" could be your valves and your pistons hitting eachother. i highly doubt that you motor is non-interferance and if it isnt and the valves and pistons hit that could mean new valves and possibly new pistons also. get it checked asap better yet take it back to the people that did your install and make them fix it. let me know how all this turns out