i see a lot of talk about aftermarket cylinder head problems out of the box.if you have had issues with any brand id like to hear about your ordeal.i am only looking for actual issues,not what someone said needs to be done,just issues that YOU have had.full force tim,we know your story so no need for you to reply.

When RHS bought out ProAction, the rocker studs where not in proper location. That bit the industry bad. Good news out of all of that was a few bigger cyl heads shops where enlisted to help Comp Cams (who then owned RHS) get the castings squared away.

Following.


Be also nice to hear what the combo is. In otherwords, are we talking 500hp engine, or 1000+hp engine with out of the box heads, sucess or issues. Cold water temps or thermostats involved.

That was also an issue on afr heads. According to tony mamo they corrected it after a certain date.

http://speedtalk.com/forum/viewtopic...=9025&start=15

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I think the issue was more of a factor of the longer valve causing the contact pattern to be too far on the exhaust side, so they had to relocate the stud location. I was still having a problem with this, but switching to a different rocker corrected the issue. there is another thread that discusses differences in rocker arms.

When I had my Edelbrocks off we checked one valve seat and it was .009 out of round, which in theory would cause the valve to walk and hunt compromising longevity, but no failure as of yet. So I'm curious about your question as well. We know that production heads have less than optimal machine work, but does it really amount to a hill of beans?

For marine stuff the biggest issue is guide clearance. I've seen some pretty out of round and crooked guides as well. Seat run out and depth variations are another thing I check for. Then of course rocker geometry and yes, with more installed height for larger lift cams you can get into a situation where the tip of the rocker starts moving outward. One thing I don't appreciate about AFR heads is they use one valve length for every big block head and many times you don't need near all that installed height. The long valves just exacerbate the geometry issues. I will also say there are a lot of variations in fulcrum lengths with rockers and it's why I always use Crane Golds for aluminum stud mount rockers. They have the right fulcrum length and show the least amount of problems with the longer valves. Push rod clearance can also be an issue with some heads, especially if you want to go to 7/16 push rods.

I saw a significant difference in tip patterns when trying 3 different brand rockers, and optimal pushrod length. For those who simply roll the engine over and look for a pattern on center of stem, and dont care how wide the pattern is, as long as its "centered" , may not ever notice a difference.

Out of a comp steel rocker, scorpion alum rocker, and crane gold, the crane had the best pattern, and closest to center of stem than the other two, on the same valve. This was on dart heads with longer intake valve.

I know some here won't be able to get past the name but for those without an agenda, this might be helpful:

https://www.youtube.com/watch?v=o5is...ature=youtu.be