I recently acquired, from eBay, a dual 48mm DCOE flange for building my '801 ITB manifold.
I will have to open up the runner ports to 50mm to match my larger throttle bodies.
I want to have an aluminum intake for the final build, but I am thinking I can dyno test with a 3d printed one to confirm it does what I want.
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While I'm waiting for UPS to unf*ck my shipping of the old head and intake, I went to the block to prepare it for deep cleaning.
I have most of the freeze plugs pulled, but the rear freeze plug is very stiff and will not budge with my drill and pry bar method, I will have to cut it out, its now lodged against the cylinder wall and one of my prybars is bent, and I am currently out of cut off discs for my Dremel. These plugs where very hard and thick compared to the cheap soft steel hones I have encountered previously.
I pulled the 7/16 main studs, to discover that the block was heli-coiled to 7/16-14. This makes perfect sense but is an issue.
I believe factory dukes came with 11mm main cap bolts. The early SD4 blocks, like mine came shipped machined off factory tooling. The build guide instructed to redrill them for the prescribed 1/2" Main studs using a 27/64 Drill for a 1/2-13 tap.
Helicoils in the 7/16-14 thread pitch require a 29/64 drill, 1/32 larger than the proper 1/2-13 tap drill, I don't have any material left to cut 1/2-13 threads.
Using a 1/2-13 helicoil would reqiure a 17/32 drill, I am not so sure I retain adequate material on the main journals at the mating flange for such a large tap size, especially at the bearing retaining tang.
I may be stuck with the 7/16 main studs, which may be adequate, just not what was prescribed by the original build and what is equipped on later SD4 blocks.
I also found a weld repair at the last main saddle, The repair looks well done, and the bearing journal looks great, maybe this was a factory done repair, since the block was purchased new by the owner, or the machine shop messed up something.
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The 2 barrel intake is lost in UPS hell, And I'm out of a fair amount of money for all of it, it seems. the label Purchased through Ebay, and lost by UPS, which makes filing a claim difficult, international support help lines, callback times, and gouging eBay fees, means I owe way over what i receive from the sale for a refund, I'm not too happy.