Emissions SB heads

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DemonDave

DemonDave

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Seeing that the later 360 heads had emissions ports adjacent to the exhaust ports that will be uncovered when headers are installed, what's the best way to plug these?

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AdamR said:
Tap them and use small allen head screws.
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Are they already drilled to accept a certain size tap or is it a drill up and tap accordingly deal? The heads are already bolted on the rebuilt engine and I'd hate to introduce a pile of swarf into the fresh engine by drilling.
 
I had to run a 13/64" bit in my son's and tap them out to 1/4"-20. I didn't have the rocker arms on his yet, stuffed a rag in the intake ports in the head, just blew them out because both vaves were shut so the shaving had to come out the exhaust ports.
 
They heads need to be removed and drilled or you'll break a tap. That would be very, very bad. Do you have a tap/drill chart? I like to drill just a hair larger in cast iron than recommended for steel to avoid the tap breakge senario.
 
Thanks for the info/advice. Taking the heads off is no biggie since the engine is still on the stand in the corner of the garage... just need some weather above zero so I can stay out there for more than five minutes...
 
I guess I should give more particulars. Don't need to drill all the way thru, 1/4" is more than enough and use never seize on the tap to catch shavings. I used 1/8" long set screws so you only need 2 good threads for them. For added security I center punched close to the edge of the hole after I put the set screws in to keep them from backing out. And I don't blame you thats just too cold. BRRRRRRRR!
 
I used JB Weld on the screws to keep em tight. They aren't going anywhere, lol!
 
ramcharger said:
They heads need to be removed and drilled or you'll break a tap. That would be very, very bad. Do you have a tap/drill chart? I like to drill just a hair larger in cast iron than recommended for steel to avoid the tap breakge senario.
Click to expand...


I did mine in the car many years ago. Not sure what size tap I used but I did not drill the holes bigger or deeper. Just ran a tap in-with lots of tap oil. Needs not to be perfect, just 5-7 threads. I used lockthight on the steel allen head plugs.
 
DemonDave said:
Seeing that the later 360 heads had emissions ports adjacent to the exhaust ports that will be uncovered when headers are installed, what's the best way to plug these?

signthankspin.gif
Click to expand...


Weld them up and grind them smooth is what was done to the 302 castings heads that I have now.
 
On my smog 360 heads the holes are already taped.Plug them with some allen plugs and high temp thread sealant.
 
mullinax95 said:
Weld them up and grind them smooth is what was done to the 302 castings heads that I have now.
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Have one hole that is buggered up and need's to welded.

What kind of welder was used on your heads?


Thanks.
John
 
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