A little info needed. I pulled the 455 out of my 71 SX convertible to correct many issues. One thing on the to do list is to replace the bolts in the choke stove as the bolt heads were snapped off. I spent a few hours today drilling out one bolt and retapping the hole. I've been very concerned about metal shavings landing in the intake, however it seems the bolt goes into an enclosed section, am I right or is this a problem? Thanks. I finally got the threads tapped deep enough to hold down the one side satisfactorily.

 

Shavings could possibly get in the crossover passage between the cylinder heads so you may want to be a little careful cleaning them out, as they could possibly land in an exhaust valve seat.

Just curious what you're drilling them out with. My experience is those bolts can be some hard metal after so many heat/cool cycles.

 

i actually was sorting out parts in the garage and measured the threaded section of the choke stove bolts on my 350 manifold.It is about an inch deep .and it is closed off at the bottom

 

So as far as you could tell the bolt area is an enclosed section, therefore any potential shavings couldn't go anywhere to cause an issue. That would be good news. I will hook up a vacuum and attach a drinking straw to go down the bolt hole just in case. The bolt is 3/4 in length, but the furthest I could retap only allows for a 5/8 bolt which snugged down fine. Now for the other side.

"Just curious what you're drilling them out with. My experience is those bolts can be some hard metal after so many heat/cool cycle"
I used a cobalt drill bit to start and then went with three larger titanium bits to clean out untill the original threads were exposed. Retapping however was a slow and tedious process. Now for the other hole...
Thanks guys for the feedback and info.