have a 428 cj with a bent pushrod. the engine was rebuilt and is still new. i do not know what type of cam. the heads have adjustable rockers and the pushrod has a cup on the top end. i need new lifters too cause they are the only thing that the engine shop left in when it was rebuilt. the valves "float" around 4000. my questions are what type of lifers and pushrods should i use if i keep the adjustable rockers.