Heads...
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
When building my 1st engine a few years back, I went the assembled route thinking that I didn't know enough. Turned out that I ended up disassembling them anyways to ensure the valves were lapped correctly and to reset the spring locks. To me now the only difference between assembled and unassembled is owning a spring compressor tool.
Intermediate
Joined: Apr 2007
Posts: 38
Likes: 0
From: Baltimore MD
It depends on which ones you buy. I buy assembled heads from Brodix all the time and they are usually on the money. I have had some issues with some other heads out there with inconsistent valve seat widths and spring heights. If you can afford paying the extra then buy them bare and have them done by a good local shop to ensure everything is where it needs to be.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Well, I just paid about $2K for a set of AFR CNC heads and DON'T like the valve gear they came with so based on my expiriences, I would go bare. My valves are at Manley Performance to serve as prototypes for new custom valve assemblies. Why AFR can't put valves in with swirl polished backsides and good machining for $2K I don't know
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Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
The higher performance (and more specialized) application they're for, the less likely you are to find an off-the-shelf complete head that meets your requirements/specs. In any event, for those who go with an assembled head, make certain that the valve springs are correct for your cam. This is vital, regardless of the build.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
World heads = cast iron valve guides like stock - you know how long those last in a street SBC.
Dart Heads = Bronze guides.
-Mark.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
-Mark.