Can I tap a head for an ac bracket on my 71/SBC 350? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BigTopGT · 06-05-2021, 09:29 AM

So, I'm in south Florida and it's starting to get warm. Since. I don't want to sweat half to death this summer, I'm looking to get the AC working again and have a Sanden compressor on hand.

The only issue is I need to get the bracket sorted out and it looks like I'm missing a bolt hole in the head that'd make a bracket work.

Can I tap the head shallow and run a bolt with some locktite to keep her in place? (Pic attached if approximately where I'd need the hole tapped)

Seriously not wanting to hit a water jacket.

Thanks in advance for the advice, fellas!

**Accelo** · 06-05-2021, 11:06 AM

You will hit water.
Possibly, you would be able to drill a through hole and then seal the bolt threads when you install the bolt.

**kwmech** · 06-05-2021, 12:42 PM

I'm assuming that is where the belt lines up? I would go down to the flat spot that is actually thick enough for threads. If you go through to the water jacket then I would install a stud with sealant on it

body bolt · 06-05-2021, 01:15 PM

I'd instead get a bracket that doesn't mount to the head. Vintage Air has some for both short and long water pumps.

NorCalC20LWB · 06-05-2021, 02:07 PM

Quote:

Originally Posted by body bolt

I'd instead get a bracket that doesn't mount to the head. Vintage Air has some for both short and long water pumps.

This...

Here's some pics of the Vintage Air brackets....

BigBird05 · 06-05-2021, 08:30 PM

Make a bracket that uses the hole that your battery ground wire is in.

BigTopGT · 06-08-2021, 09:22 PM

Quote:

Originally Posted by BigBird05

Make a bracket that uses the hole that your battery ground wire is in.

This bracket setup uses that hole, but the second hole closer to the block

Maybe I can make a bracket that'll reach the water pump boss and make it easier on myself.

I don't want to throw away a brand new bracket, so until it's LS swap time, I'd prefer to make this one work, if possible/practical.

MARKDTN · 06-09-2021, 12:40 PM

I would not drill the head. I know some will say no problem, but it's not flat there so it will be an issue to get it exactly where it needs to be and drill it at the correct angle unless you take it off and fixture it. There is also the issue of proximity to the water jacket, you don't know how thick that wall is. To me, too many unknowns to risk it. My .02

**HO455** · 06-10-2021, 12:59 PM

I wouldn't chance it. Too many variables the material thickness, getting the hole straight, having the bracket sit square on the head and not twist when the bolts are tightened . The odds of success aren't good and would get worse over time.
I believe that vibration over time would lead to problems. I suggest looking for a stock bracket like this to modify.
Props to Bigdav160 for the photo.

**dmjlambert** · 06-10-2021, 06:24 PM

My 350 engine with short water pump has an Alan Grove Components Inc A. C. Compressor mount 113R that I got as part of my Original Air kit. It mounts using 1 water pump bolt and 2 exhaust manifold bolts. It comes with appropriate spacers for ram horn or drop type exhaust manifolds or headers, so it is versatile.

06-05-2021, 09:29 AM	#1
BigTopGT Registered User Join Date: Apr 2019 Location: Fort Lauderdale, Florida 33311 Posts: 103	Can I tap a head for an ac bracket on my 71/SBC 350? So, I'm in south Florida and it's starting to get warm. Since. I don't want to sweat half to death this summer, I'm looking to get the AC working again and have a Sanden compressor on hand. The only issue is I need to get the bracket sorted out and it looks like I'm missing a bolt hole in the head that'd make a bracket work. Can I tap the head shallow and run a bolt with some locktite to keep her in place? (Pic attached if approximately where I'd need the hole tapped) Seriously not wanting to hit a water jacket. Thanks in advance for the advice, fellas! Attached Images

06-05-2021, 11:06 AM	#2
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,295	Re: Can I tap a head for an ac bracket on my 71/SBC 350? You will hit water. Possibly, you would be able to drill a through hole and then seal the bolt threads when you install the bolt.

06-05-2021, 12:42 PM	#3
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,628	Re: Can I tap a head for an ac bracket on my 71/SBC 350? I'm assuming that is where the belt lines up? I would go down to the flat spot that is actually thick enough for threads. If you go through to the water jacket then I would install a stud with sealant on it

06-05-2021, 01:15 PM	#4
body bolt Registered User Join Date: Oct 2020 Location: Albuquerque, New Mexico Posts: 474	Re: Can I tap a head for an ac bracket on my 71/SBC 350? I'd instead get a bracket that doesn't mount to the head. Vintage Air has some for both short and long water pumps.

06-05-2021, 08:30 PM	#6
BigBird05 Registered User Join Date: Aug 2019 Location: Cheraw Posts: 1,300	Re: Can I tap a head for an ac bracket on my 71/SBC 350? Make a bracket that uses the hole that your battery ground wire is in.

06-09-2021, 12:40 PM	#8
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,165	Re: Can I tap a head for an ac bracket on my 71/SBC 350? I would not drill the head. I know some will say no problem, but it's not flat there so it will be an issue to get it exactly where it needs to be and drill it at the correct angle unless you take it off and fixture it. There is also the issue of proximity to the water jacket, you don't know how thick that wall is. To me, too many unknowns to risk it. My .02 __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project

06-10-2021, 12:59 PM	#9
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,350	Re: Can I tap a head for an ac bracket on my 71/SBC 350? I wouldn't chance it. Too many variables the material thickness, getting the hole straight, having the bracket sit square on the head and not twist when the bolts are tightened . The odds of success aren't good and would get worse over time. I believe that vibration over time would lead to problems. I suggest looking for a stock bracket like this to modify. Props to Bigdav160 for the photo. Attached Images __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 Last edited by HO455; 06-10-2021 at 01:34 PM.

06-10-2021, 06:24 PM	#10
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,859	Re: Can I tap a head for an ac bracket on my 71/SBC 350? My 350 engine with short water pump has an Alan Grove Components Inc A. C. Compressor mount 113R that I got as part of my Original Air kit. It mounts using 1 water pump bolt and 2 exhaust manifold bolts. It comes with appropriate spacers for ram horn or drop type exhaust manifolds or headers, so it is versatile.



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