Blocking air holes in heads

[7elk]

Anyone have a good idea to block the exhaus air holes in '75or'76 302 heads? A bolt broke off in removal and I would rather block them than replace the exhaust piece.

 

[Nobody]

Look up Thermactor plugs at summit.

 

[Explorer]

With the bolt broke, try a freeze plug.

 

[barronj]

I had my hands on a set of heads recently that had (what looked like) JB weld jammed in the port.

There's more than one way to skin a cat.

 

[Bronco_46256]

I have done it on two trucks.

Take some JB weld, mix it and fill the holes with it.

Then, take a galvanized washer a little larger than the hole and put a bolt through the center.

Bolt the washer over the hole with the JB inside and let dry. Make sure the hole is completely covered by the washer and you see a small amout of JB weld past the edge of the washer.

Did it on my old '75 and have it currently on my '68. Never had a problem with either one.

 

[ugly74]

dunno what size those are...
but on the 360 in my Dodge, I tapped in some lead that I'd plucked from some .22s. decade later and they're still there!

 

[jon705]

Some good suggestions here. Is the engine out of the vehicle? If so I'd recommend drilling and tapping those bolt holes. I bolted two rectangular pieces of sheet metal over the exhaust holes. Applied gasket material around the exhaust holes prior to tightening the rectangles and it has worked fine.

 

[ljspop]

On my 84 Heads, there were threaded inserts to block the ports on the front of the heads and allow accessories to bolt up. I went to the dealership and bought an extra set and screwed them into the back of the heads too.

Not sure if that translates to 75/76 heads.