Twin Cam Rocker Boxes

[Garagerat]

What year(s) rocker boxes fit an 07 96" TC?

[xlfan]

At least all years TC up to M8

[rigidthumper]

The later ones have a bit more clearance for the springs, but all beehive heads (05 and newer 96/103) will work with any TC boxes.

[Garagerat]

Thank you.

[tbird]

So your saying 99-04 rocker box covers won't work on the newer twin cams? I have a set of chrome covers off a 2000 tc that I was going to put on a 12 switchback just for looks. Don't care for the dull aluminum covers it has.

[kd]

Dry fitting the covers with "clay" will tell you if there is any clearance issues with the valve train.  That will depend on your cam specs (ie. lift and the valve spring collar radius).  There is lots of information available in an online search how to do this simple operation.  For example the webbing found above the rocker arm often needs to be ground away down to the under surface of the cover and clay will measure your results before you assemble for good. Also attention to the side of the cover and base for valve spring collar is important as some manufactured components may be more robust and reduce that clearance.  Even installing the cover and having it slip may reduce clearance on the best of covers. Doing this is definitely recommended when other than OEM cams and valve train components are used as they are often built more for component performance and reliability than they do for OEM fit.  Engine builders understand this and it's one of the things you may be paying for when having them "build" your engine for you. 

[rigidthumper]

So your saying 99-04 rocker box covers won't work on the newer twin cams? I have a set of chrome covers off a 2000 tc that I was going to put on a 12 switchback just for looks. Don't care for the dull aluminum covers it has.

They will fit and work fine on your FLD, as you have beehive valve springs.

[SP33DY]

Dry fitting the covers with "clay" will tell you if there is any clearance issues with the valve train.  That will depend on your cam specs (ie. lift and the valve spring collar radius).  There is lots of information available in an online search how to do this simple operation.  For example the webbing found above the rocker arm often needs to be ground away down to the under surface of the cover and clay will measure your results before you assemble for good. Also attention to the side of the cover and base for valve spring collar is important as some manufactured components may be more robust and reduce that clearance.  Even installing the cover and having it slip may reduce clearance on the best of covers. Doing this is definitely recommended when other than OEM cams and valve train components are used as they are often built more for component performance and reliability than they do for OEM fit.  Engine builders understand this and it's one of the things you may be paying for when having them "build" your engine for you. 

When double and triple coil valve springs are involved, I check side clearance on the lower cover by locating them with the little tapered Evo lifter block alignmemt screws in the umbrella breather holes. Then I use them again for final assembly alignment after clearance work is done. That way they always end up in the same position. Beehive and conical springs eliminate that problem.  I use an 0.050" wire spark plug gap checker for a clearance gauge.

[kd]

Good advice.  I have found that the covers easily slip out of alignment to the right side when torqueing down the fasteners.  My cure is to cut some aluminum strips  from a beer can and make rolled sleeve inserts to be used like thin dowels for the fastener holes before installing the top cover. They do a good job locking the cover in place and the edges are held in alignment with the lower section.  IMO a simple invisible fix.