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I just recently had my engine apart to do some misc stuff to it and noticed a slight wear pattern on the valve tips where the rockers ride. The wear was not in the center but much closer to inside of the valve tip.

My engine is a 74 model 351w with edelbrock rpm heads, cam, lifters etc with crane 1.6 ratio roller rockers.

Based on research that indicates I need a bit longer pushrod. Bought one of the comp cams push rod length checkers and started lengtening the push rod and checking where the roller tip was contacting the rocker.

I went thru this several times and it seemed to be getting dialed in but next thing you know I had lengthened it considerably to the point the adjusting nuts only have about .25 of thread.

Any ideas? my combo is not that weird I should be having this much of an issue.

The original pushrods were 8.152 and where I am at now they would need to be 8.5 and still not making contact in the center.

I was taking a green sharpie and marking the roller tip good and rotating engine over a couple times and the sharpie ink would leave a good mark on the tip.
 

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OK, here is the information you requested! The first link is by comp cams and is a very basic read that may get you started, then go to the next 3 links for an in depth description of how to check for pushrod length. Let us know how it comes out!

http://www.compcams.com/information/Products/Pushrods/


http://sbftech.com/index.php/topic,317.msg38894.html#msg38894

http://www.carcraft.com/techarticles/116_0401_setting_pushrod_length/index.html

http://www.circletrack.com/techarticles/ctrp_0609_pushrod_length/index.html
 

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Sorry for the typo's above.

Let me clarify my last message. If you don't pump up the lifters they will collapse some depending on how they sit in their channel. You can check this by pushing on the back of the rocker arm. If they collapse a little, you will know that they are not pumped up. When I had this problem, I removed the distributer and used a rod to turn the oil pump. It is important to center Roller Rockers on the valve stem. If you don't, you could cause wear in the valve guides
 

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You can use a sold lifter as well for checking.
I'd not get so hung up on being dead center but focus on the wear pattern/witness mark thickness, smaller the better.
I'd check both intake and exhaust on both banks
 
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