I'm getting ready to replace my valve seals, so I figured why not throw on some 1.6 roller rockers while I'm at it (Mod excuse) They are for my '85 305HO. I'm going to get Comp Cam Magnum's 1.6 roller tip, non-self aligning.. Do I need different push rods? should I replace them even if I don't? What else should I do while I'm at it? I should be ok with the old valve springs correct? The car only has 60k on it....

Thanks!

 

Oh yeah, will the pushrod slots/holes need to be lengthened? if so can this be done with the heads on the engine? Heads are stock L69's

thanks

 

You might need to lengthen the slots, there's no way to predict. On about half the motors I have ever dealt with, at least on eslot needed it. It cannot be done on the car unless you are willing to risk getting metal chips in the motor.

The push rods do not care whether the rockers are rollers or not. You lengthen the push rods as cam lobe lift increses, because the tip of the lobe doesn't get taller, but rather the back side of it gets shorter. So as you add more and more lobe lift the lifter & push rod sinks farther and farther into the block, and the rocker tips farther and farther back, which causes the tip of the rocker to have to move sideways across the valve stem tip too much.

As long as those heads are stock, the increase in ratio won't do much of anything. Stick with the 1.5 version of those rockers. Be prepared for problems with the valve covers: the oil separator may not fit down between the rockers.