The only fix will be through bolt logs to stay as you are.....They are the only log style that will not leak at ports.  You can put a good set of felpro on them.  I have a set right now that needs a polish and I usually sell em on ebay for 500.  Will let em go for 350 + ship and they come with the 16 mounting bolts.

This is a ford issue....

Have the logs machined back to flat. Then run a good MLS exhaust gasket with some hi temp silicone on each side.

Have the logs machined back to flat. Then run a good MLS exhaust gasket with some hi temp silicone on each side.

This is actually what I've ended up doing. Although thy aren't exactly machine flat. More like belt sanders flat. I think (I hope) the silicone will make the difference. I used the high temp copper basket maker. We shall see.

Leaving for sandpoint havasu Thursday a.m. for a week.  Hope they hold up.

I had the same problem with my SBC, had the manifolds suraced and used no gaskets, been almost a year now without any leaking

If you have a 460...the through bolt is the only kind that will not leak!!!!!!!!!!!!!!!!  Go spend money on resurfacing your small flange ford exhaust and after a few trips it will be leaking again somewhere. This is a ford issue not CHEVY!!!!!!!!!! If you have this style then your not having a problem regardless of the surface being perfect. A good set of felpros and your done. No silicone!

Is it often you have a set of these lying around? I will definitely be looking to swap to this type manifold but dont quite have the cash at the moment. These hardin style look like they'll flow a LOT better too as my panthers have an exhaust port that is roughly 60% the size that those look to be.

FWIW, I tried the silicone/new gaskets route after resurfacing and after 8 days of hard running at havasu, i've got an 1/8" gap between flange and head in one spot. I think where some manifolds in better shape might benefit from resurfacing, thicker gaskets etc.., mine have been on and off this motor too much in the last 30 years and now have too little meat where the nuts need to apply all the force to accomplish and maintain a good seal.