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? 

you can if you want.you see this lots of times.doesnt hurt anything

From my experience, If you put the higher ratio ones on the exhaust you will come off the corners harder if the track is sticky.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I would have thought putting them on the intake side would have been better.when I bought the engine the guy said it really ran strong. But when you see things like this you have to wonder if it has other issues that the rebuilder overlooked.it came out of a pickup it had rams horns light 3 speed tranny with old style 2 bbl carb.Does anyone have any of the high ratio rockers ? I have everything for a truck that came off this engine maybe we can trade? I gave up trying to sell parts with the high cost of shipping.

I have also seen mixed rockers, I think they just replaced worn ones with whatever they had on hand. As to where to put the high ratio rockers if you don't have a full set? Intake would be my guess also, I don't see a problem.