Topic: Hole in the casting by the #4 plug

[interstatewingrider]

I picked up a 350-4 that's a little rough, and am trying to get it running correctly.  I cleaned out the tank (eew) and put in fresh oil and battery.  The #1 bowl overflowed.  I tapped it with a big screwdriver, and that stopped overflowing. It will start, but struggles to run.  There's no fire in #1 and #2. Those two pipes don't get hot.  Spark looks good.  I put new points in and adjusted them, and while replacing the plugs I found this hole in the head casting behind #4 plug.  It looks like it corroded through the casting.  It doesn't penetrate the cylinder, just the cam/valve assembly cavity.  I'm thinking JB Weld. 

Have any of you come across anything like this?
Thoughts?  Comments?

[Don R]

 I'm not that familiar with that motor but I'm wondering if those holes were open to the fin space and a mud dauber closed them up for you.

 The carb main and pilot jets are extra tiny and tiny things can plug them up, especially when bad gas is present.

[MauiK3]

Lets see the bike?