Rocker Clarification is up!!!

Alan Roehrich · 01-24-2012, 05:29 PM

There already is a rocker ratio tolerance, it is +0.0/-x.x, as they don't seem to penalize anyone for not having enough ratio. You can have the stock blueprint ratio, or less, but not any more than stock. That's tolerance enough, a + 0.0/-x.x is an industry accepted tolerance range.

NHRA checks lift at the retainer, then divides by lift at the cam to get rocker ratio. I'm allowed 0.520" at the retainer, I run 0.518", with 0.306" lobe lift on the cam, for a 1.69:1 rocker ratio.

In Stock, we have to use pushrod length to correct lift, in most cases. That does not change, it's just that with aftermarket roller rockers, you'll need to start from scratch, and get the pushrod that gives you the correct lift, without exceeding the allowed rocker ratio.

01-24-2012, 05:29 PM	#24
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,113 Likes: 1,571 Liked 1,827 Times in 414 Posts	Re: Rocker Clarification is up!!! There already is a rocker ratio tolerance, it is +0.0/-x.x, as they don't seem to penalize anyone for not having enough ratio. You can have the stock blueprint ratio, or less, but not any more than stock. That's tolerance enough, a + 0.0/-x.x is an industry accepted tolerance range. NHRA checks lift at the retainer, then divides by lift at the cam to get rocker ratio. I'm allowed 0.520" at the retainer, I run 0.518", with 0.306" lobe lift on the cam, for a 1.69:1 rocker ratio. In Stock, we have to use pushrod length to correct lift, in most cases. That does not change, it's just that with aftermarket roller rockers, you'll need to start from scratch, and get the pushrod that gives you the correct lift, without exceeding the allowed rocker ratio. __________________ Alan Roehrich 212A G/S