This probably has been covered in the past but too lazy to look up past posts. I bought a used engine to replace my 272 in my 56 customline.it is a 292 not a 312 as suggested but I knew it was no doubt a 292.the problem is it has 5 high ratio rockers and the rest are low ratio rockers. They are randomly located  so I think it was a case of someone not knowing the difference between them ,my question is can i buy 3 more and use them just on the intake side or would that not be a wise idea?