Hey gents, first off I've been reading and researching here for months in preparation for my first 390 build for my grandfather's 75 highboy. So, thank you for the countless resources and knowledge I have gained from all of you.

My block is back from the machine shop and I'm ready to start assembly. I was finishing up some oil mods (drilled out the pump to filter passage, chamfered some holes and opened up the off-center passages in the main saddles) and I decided to tap my oil valley plugs for 1/4 NPT plugs. I started at the passage up from the filter where it intersects the top center main oil passage. I drilled out the passage about 5 inches down using a 7/16 bit (same size needed for the thread tap and only slightly larger than the passage was already). When I finished I noticed during cleanup that my now 7/16 passage had cut into the passenger side lifter passage just behind the cam retainer bolt. CRAP!!

The hole is tiny, maybe a pinhead at most. What problems could this cause if left alone? How could I fix it? Maybe tap the cam retainer bolt threads deeper and use a longer bolt to cover my bobble? I know I have read of other guys openening this same galley, has anyone else seen this issue or am I just a moron??
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Thanks fellas

-Justin

 

I really thought after months of reading and researching through this site that everyone here was eager to help and pitch in. I am machining a bolt to cover my bobble. Should prove to be a solid fix. I'll post pics as I go in case some poor newbie like me has a similar issue.

 

FTE is good for general FE help but for specilialized questions like yours you're more likely to get the help you need at one of the FE Forums.

 

AND bad advice is worse than no advice. I am curious to know the answer to your question.
I could see a loss in oil pressure, flooding the lifter and pumping too much oil on top of the head....but I'm not sure. Just thinking it through.

 

There are more than 200 views on this thread at this time.

I'd really like to help, but I don't even know what to say at this point.

If you had better pictures of the issue, maybe someone would chime in.

I have a feeling many here just gasped and didn't know what to say

Oh, and many of the old timers do not visit more than once a week or two ...

 

I don't have a bare block here to look at in order to try to give a answer, and although I looked at this thread the day you asked the question, I still haven't been able to wrap my head around why you drilled 5 inches through two oil galleys when you should have stopped at the first one that was only 1 inch away.
Also without a block to look at I can't figure out what the passage feed. I was thinking the lifter feeds are farther back near the rear of the block.