The Aluminum Block Slant Six uses special extended thread length cylinder head and main cap bolts.
Installation of a windage tray has been a challenge because the factory never offered hardware with windage mounting provisions.
ARP worked with us to develop some really nice custom head and main studs to address these issues with the Alm. SL6.
The Alm. Block SL6 head bolt has a threaded section (7/16 - 14
is 1/2 inch longer than the cast iron block's head bolt. (See photo
with dashed red line at the thread's starting point.) The cast iron
block's head bolt is shown on the right, next to the special ARP head
stud for the Alm. Block SL6.
The white line in the lower right view shows the extra long (1.6) thread length next to the block's bolt boss. It takes some work to get these extra long studs to completely screw in, flush to the top deck.
The Alm. SL6 main bolts are much longer and have a recessed shank. This allows oil flow around the bolt to the upper cast iron main cap's oil passageway & feed hole.
The "prototype" layout I developed for the ARP studs is based on the length of the Alm. block's bolt bosses. The stud's course thread is made longer to allow for maximum engagement into the block's threaded boss. You will note that the head stud print shows two different lengths. The .100 longer stud, (5.9 total) will require the user / installer to carefully redrill and flat bottom tap each of the 14 head bolt bosses. Measure and mark your drill and the tap so you do not go too deep and break out the bottom of the boss. (See photo insert. I epoxy repaired a boss I went too deep on.) All the main bolt bosses I have done so far were already drilled extra deep. I just retap each one with a bottoming tap. These did not need additional redrilling like the head bolt bosses. (ARP will furnish the head studs to either length so unless you are building a super trick race engine, I would get the shorter (5.8) one to save yourself work) - DD
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Copyright © 2002 - Doug Dutra, all rights reserved