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Discussion Starter #1
I have 333882 heads on my 350 engine.
I'm adding AC, mounting the compressor on the passenger side of the car with an inboard AC bracket that requires two holes on the head to mount it.

I didn't notice till I went to bolt it on that the passenger side head only has one hole facing forward. Looking the heads over I see that both heads have 3 holes on one end, and one hole on the other end, but when mounted the passenger side head has the 3 holes facing backwards and the one hole facing forward.

The passenger side had looks like it is faced right where I need another hole.
Is the material thick enough here to just drill and tap another hole?
Has anyone done this before with success?

Appreciate any input, thanks!
 

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More for Less Racer
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If the casting has the contact surface thick enough it was faced of and not just left shallow and as-cast, it is thick enough to drill and tap for the bolt. Just be aware to not drill too deep, these holes were never drilled much beyond 3/8-3/4" deep, and you'll need a bottom tap to finish the hole and get threads the full depth. If you do break through it isn't a huge deal, you'll just need sealer on the bolt threads to prevent a leak.

I've done it once, but it was 30 years ago.....hard for me to believe guys are still using that crap 882 head on anything anymore other than rules mandated lower level circle track stuff.
 

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Discussion Starter #3
If the casting has the contact surface thick enough it was faced of and not just left shallow and as-cast, it is thick enough to drill and tap for the bolt. Just be aware to not drill too deep, these holes were never drilled much beyond 3/8-3/4" deep, and you'll need a bottom tap to finish the hole and get threads the full depth. If you do break through it isn't a huge deal, you'll just need sealer on the bolt threads to prevent a leak.

I've done it once, but it was 30 years ago.....hard for me to believe guys are still using that crap 882 head on anything anymore other than rules mandated lower level circle track stuff.
Thanks for input.

yea I know the heads are crap, but its a really old build from the late 70's, maybe the early 80s. I'll be gradually building up a 383 engine with better heads, but that's going to take awhile.
 

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I've seen early heads that people have drilled and tapped and the problem I've seen with all of them is that the surface facing out is not flat nor parallel to the plane the belt runs on.

Any spacers will need to have the faces modified to match the angles.
 

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I have 333882 heads on my 350 engine.
I'm adding AC, mounting the compressor on the passenger side of the car with an inboard AC bracket that requires two holes on the head to mount it.

I didn't notice till I went to bolt it on that the passenger side head only has one hole facing forward. Looking the heads over I see that both heads have 3 holes on one end, and one hole on the other end, but when mounted the passenger side head has the 3 holes facing backwards and the one hole facing forward.

The passenger side had looks like it is faced right where I need another hole.
Is the material thick enough here to just drill and tap another hole?
Has anyone done this before with success?

Appreciate any input, thanks!
There are some variations in this casting some don't have the upper pad on one end and the others have it on both ends. Which do you have?

If the pad is there but undrilled and untapped then yes you can but you also need a bottoming tap (no taper) to get useful threads which you need to have all the way to the bottom of the hole. Without a pad the casting thickness is iffy as to putting this king of stress on it.

Bogie
 

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the 'Duracell Project'
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if the machined pad is there then drill away, i've done it many times over many years
look at other holes in similar location on the other head to figure out how deep to go

the front motor mounts on old chevy cars and trucks were standard for years
slowly the 4 bolts were eliminated as accessories move higher on the block
still have the machined bosses on the block but rarely is there more than 1 hole

 

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Discussion Starter #8
Can you modify your bracket so it uses a water pump bolt?
This bracket doesn't look like any mods would work out too well.
Was looking at bills inboard ac bracket, and it mounts to the single hole, and uses a water pump bolt and It looks like an intake bolt too.

My go with that bracket, but then it won't match the bracket I have on the alternator.
 

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Discussion Starter #9
There are some variations in this casting some don't have the upper pad on one end and the others have it on both ends. Which do you have?

If the pad is there but undrilled and untapped then yes you can but you also need a bottoming tap (no taper) to get useful threads which you need to have all the way to the bottom of the hole. Without a pad the casting thickness is iffy as to putting this king of stress on it.

Bogie
Yea, the pad is there.
So maybe I can drill it.
 

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Discussion Starter #10
follow up

I was able to drill and tap a hole for another accessory hole.
The pad on the head did not line up with the primary hole in the bracket, but the bracket had a contingency tang with a hole in it that lined up with the pad where I drilled the hole, so it all worked out.

Been working on a lot of other things so took awhile to get back here and post update. Thanks for all the input.
 
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