The 351-W that is in my 55 sunliner started to make a lifter noise when starting up after sitting all night after a 3000 mile trip last fall and was told it could be the lifter bores are worn too much,of all the motors I had thorugh the years I never ran into this. The builder supplied the block so I do knot know how many miles were on it and it does have the wrong cam for the application but dont want to spend too much money in it since I am planning on going back to a Y block. I put a gauge on the motor and the oil pressure starts to go up when cranking and on high idle will go up to 70 and then when warm comes down to 30 when hot at regular idle so I dont think pressure is the problem,it will make noise about a minute after firing up and always had a little noise coming from the top but nothing I would consider serious but a minute for the lifters to pump up seems a little long for a rebuilt motor with about 10,000 miles on it.