Chevy Impala SS Forum banner

Aluminum heads and stripping header bolts.

1941 Views 10 Replies 7 Participants Last post by  Heavy_SS
So I am having an issue with stripping 2 header bolt holes on my aluminum heads, good news is they are on cylinder 1, so its easy to get at.

I had a problem of the bolts keep backing out and loosening. So I got overzealous and stripped them.

On a friends recommendation I plan on a Helicoil thread repair kit found in the link

http://www.helicoil.in/helicoil.htm#gen

I would like to know if anyone has used this product or run into this issue before, if so what was your resolution. Also what which size I need.

I have LT1 aluminum heads and Clear Image Tri-Y Gen 1 headers and the 12 point bolts he supplies with the header package.

TIA guys!!!
1 - 11 of 11 Posts
A helioil of stainless steel makes for one very strong repair. Just do your best to get them in straight and to the proper depth. As for the size, just go with the stock size of 3/8"-16.
We used them several times on old big block Chevy aluminum heads. Just follow torque specs, or use lock washers or header bolt locks:

http://www.summitracing.com/parts/STG-8911/
A helioil of stainless steel makes for one very strong repair. Just do your best to get them in straight and to the proper depth. As for the size, just go with the stock size of 3/8"-16.
Ditto on what he said. You have to the arm strength of a Gorilla to strip out a Heli Coil.
Ditto on what he said. You have to the arm strength of a Gorilla to strip out a Heli Coil.

Well I have been working out.

Thanks for the info guys.
Once you get threads back in the head, you might want to invest in studs. Some fitting will be required. I like the stainless ones, but any of them will do:
http://www.summitracing.com/search/Part-Type/Header-Fasteners/Brand/ARP/Fastener-Style/Stud/Make/CHEVROLET/Engine-Size/5-7L-350/Thread-Size/3-8-16-in/?Ns=Rank|Asc
Once you get threads back in the head, you might want to invest in studs. Some fitting will be required. I like the stainless ones, but any of them will do:
http://www.summitracing.com/search/Part-Type/Header-Fasteners/Brand/ARP/Fastener-Style/Stud/Make/CHEVROLET/Engine-Size/5-7L-350/Thread-Size/3-8-16-in/?Ns=Rank|Asc
I looked those up and if I have anymore trouble I'm going that route.

I want to stop spending time on the engine, for now and get it on the road. The paint needs attention and so do the ******* door panels.
Like Glen said teh SS ones work great.
I didnt check the links, but make sure you are using 1" long bolts. They help out a lot. I have had good luck with them on the aluminum heads.
Once you get threads back in the head, you might want to invest in studs. Some fitting will be required. I like the stainless ones, but any of them will do:
http://www.summitracing.com/search/Part-Type/Header-Fasteners/Brand/ARP/Fastener-Style/Stud/Make/CHEVROLET/Engine-Size/5-7L-350/Thread-Size/3-8-16-in/?Ns=Rank|Asc
Should have done this as well. :confused: I'm hoping I didn't strip out the back of the driver side head. OP good luck.
Should have done this as well. :confused: I'm hoping I didn't strip out the back of the driver side head. OP good luck.

Thanks
That one is a bitch as is the last one on the passenger side.

Hopefully Napa will have them in stock.
***update***

Well after figuring out how to get the holes drilled as the upper control arm knuckle is in the way. I decied to remove the motor mount bolts and raise the engine. Along with purchasing a right angle air drill.

Jacked the motor up SLOWLY about 4 inches after I removed the header and spark plugs, wires and gasket. The softer center piece of Percy's gaskets stuck to the head so I thought might as well leave it there.

Got the holes drilled and re-tapped and the steel spring inserts installed last night. Test fitted the bolts. No problem, it fits solid and tight and bloody strong.

Had my brother in law helping me but he had to get home to pack for a week trip. Plus it was 7 o'clock and I was running out of fluid in my body. It was 96 degrees and me being a fat Minnesotan I was sweatin' like Cracka' after a week of no booze and smokes.

Tonight and into the week I'll get her buttoned up and back together.

I can assume that the reason the bolts were off set of each other is because of the AC compressor.
See less See more
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top