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A difference? Yes, but it depends.
By Gerry Proctor - 05/25/2006 6:42:45 AM; IP 137.242.1.15
You would need adjustable rockers (and companion pushrods) if you were running a solid lifter cam. You might (heavy emphasis on the "might") need them for some hydraulic cams too.

You must use an adjustable setup if you are using anti pump-up lifters. The reason for this is that in order for anti pump-up lifter to function properly, preload is usually limited to .020", which is not achievable with a non-adjustable setup. On a standard lifter, the recommended preload range is .060-.080 which is done with a non-adjustable valvetrain.

It also might be necessary, or at least beneficial, to run an adjustable valvetrain with some high-lift, long-duration hydraulic cams. As you get over .550" lift, some cam grinders recommend an adjustable valvetrain. This isn't a carved in stone rule.

If you run adjustable rockers, you also have to run companion pushrods. Pushrods for adjustable FE rockers use a ball and cup design, while non-adjustable rockers use a ball and ball design. There is also an inconsequential rocker ratio difference between the two (1.73 to 1.76) but that ratio difference is a red herring, should it come up.

Regarding a performance difference...if your cam grinder or lifter manufacturer didn't specificially caution that you need an adjustable valvetrain, then you have nothing to gain by converting.

I am using an adjustable setup on my 390, but that's only because I'm using anti-pump-up lifters.

If someone is telling you that you do need an adjustable setup, ask them for justification and see if it coincides with fact. I have no idea why someone is telling you that you do and don't know what their motivation would be for doing so. The only valid reasons are running a solid cam for lash adjustment, or that you can not achieve proper hydraulic lifter preload.
This thread, so far...
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Collapse <a href=../ForumFE/reply.aspx?ID=27392&Reply=27392><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor27392" onclick="return false;">pushrods</a>&nbsp;-- <font color=#0000ff>joe cass, <i>05/20/2006</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=27392', contentMargin: 60, icon: $('anchor27392') }); </script>  pushrods -- joe cass, 05/20/2006
Collapse <a href=../ForumFE/reply.aspx?ID=27405&Reply=27392><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor27405" onclick="return false;">Use the factory pushrods.</a>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>05/22/2006</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=27405', contentMargin: 60, icon: $('anchor27405') }); </script>  Use the factory pushrods. -- Gerry Proctor, 05/22/2006
Collapse <a href=../ForumFE/reply.aspx?ID=27406&Reply=27392><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor27406" onclick="return false;">RE: Use the factory pushrods.</a>&nbsp;-- <font color=#0000ff>joe cass, <i>05/22/2006</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=27406', contentMargin: 60, icon: $('anchor27406') }); </script>  RE: Use the factory pushrods. -- joe cass, 05/22/2006
Collapse <a href=../ForumFE/reply.aspx?ID=27408&Reply=27392><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor27408" onclick="return false;">That's right. n/m</a>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>05/23/2006</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=27408', contentMargin: 60, icon: $('anchor27408') }); </script>  That's right. n/m -- Gerry Proctor, 05/23/2006
Collapse <a href=../ForumFE/reply.aspx?ID=27417&Reply=27392><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor27417" onclick="return false;">RE: That's right. n/m</a>&nbsp;-- <font color=#0000ff>j cass, <i>05/24/2006</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=27417', contentMargin: 60, icon: $('anchor27417') }); </script>  RE: That's right. n/m -- j cass, 05/24/2006
Collapse <b>A difference? Yes, but it depends.</b>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>05/25/2006</i></font>A difference? Yes, but it depends. -- Gerry Proctor, 05/25/2006
Collapse <a href=../ForumFE/reply.aspx?ID=27421&Reply=27392><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor27421" onclick="return false;">RE: A difference? Yes, but it depends.</a>&nbsp;-- <font color=#0000ff>walt, <i>05/25/2006</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=27421', contentMargin: 60, icon: $('anchor27421') }); </script>  RE: A difference? Yes, but it depends. -- walt, 05/25/2006
Collapse <a href=../ForumFE/reply.aspx?ID=27423&Reply=27392><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor27423" onclick="return false;">That only works with a solid cam, Walt.</a>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>05/25/2006</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=27423', contentMargin: 60, icon: $('anchor27423') }); </script>  That only works with a solid cam, Walt. -- Gerry Proctor, 05/25/2006
 RE: That only works with a solid cam, Walt. -- walt, 05/25/2006
Collapse <a href=../ForumFE/reply.aspx?ID=27422&Reply=27392><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor27422" onclick="return false;">RE: Use the factory pushrods.</a>&nbsp;-- <font color=#0000ff>walt, <i>05/25/2006</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=27422', contentMargin: 60, icon: $('anchor27422') }); </script>  RE: Use the factory pushrods. -- walt, 05/25/2006
 RE: Use the factory pushrods. -- j cass, 05/25/2006
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