no oil pressure

It may be easy to fix but this is a new motor 270 miles . Ok it broke the #2 intake pushrod. cracked the ex pushrod. both about 2/ 2 1/2 from the rocker end, pulled all of them on that side . ever one was scuffed up or cracked about the same distance from the rocker. Remember 270 miles. checked the heads. one is a#4027596 which is a 71-89 I think the other is a 4448308 which is a 89-92 roller tappet head I read. Also the valve cover on the 308 head had to be notched to clear on the other side it didn't. The intake was flush on the 308 side but not on the other side. I need some input will these heads work together ok and why were all the pushrods scuffed up???