That scares me . I never seen when you had to tap a lifter in with a wrench pulling old ones out is a different story . Go to any parts store and buy a lifter puller and a can of liquid wrench, spray around the lifter, turn the engine over untill the lifter comes all the way up . twist lightly back and forth while pulling untill it comes out. use cam lube , rub some in the lifter bore rub some oil on the outside of the lifter .before you put the intake on , go to GM and buy abottle of there oil suppliment you cant beet it! pure it right in the lifter valley along with youre new oil. dont wait to put the valvecovers on to put oil in it better lubrication this way .fill oil filter with oil prime oil ;pump if you can .reasemble and take youre time!!!@!