Exhaust/int. manifold bolt holes and muffler advice - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hevymetl · 06-29-2018, 08:25 PM

So I bought a new front pipe to replace old rusted one and while removing discovered the old exh manifold was cracked in several places and severely rusted. Ordered new one, installed, but discovered a couple of “soft” bolt holes thAt hold it on. What’s the best way to address this? Also, any advice on a good sounding muffler for this 250 6cyl, that’s readily available? P.O. had a canister looking one with a Toyota stamp on it. The ends are horribly disfigured from a crappy welding job and I’d just assume replace it.

Thanks, John.

shp4man · 06-29-2018, 11:40 PM

Not sure what soft bolt holes means- are they stripped?

hevymetl · 06-30-2018, 08:22 AM

Yes. Script. I can get them pretty tight but if I go past a certain point it strips. I have the ones in question as tight as they will go and the truck actually runs pretty good with 0 exhaust leaks. Obviously it's not right but will do for now I guess. Just wondering what the best course of action was to remedy that situation. I'm still on the fence as to whether I'm going to pull it and replace it with a V8 but for now I just want to drive it.

vin63 · 06-30-2018, 08:54 AM

Are you referring to the threads in the cylinder head are stripped?

Regarding a muffler, check in with a local exhaust/muffler shop and they should be able to steer you in the right direction for what you are wanting. I went with some Walker mufflers (galv. coated inside and out) on my Tempest and Riviera restorations since i wanted something really quiet. I run Borla mufflers on my hot rods.

**Getter-Done** · 06-30-2018, 09:30 AM

If your going to swap the engine later these will repair your threads for awhile.
https://www.autozone.com/test-scan-a...tem/557090_0_0 This Is just a 3/8 x 16tpi example.
Make sure to get the correct size for your studs or bolts you are using. As I am not that familiar with a 6 cyl.
Also if you attempt this make sure not to drill any deeper than the hole already are. Best way to do that is to put a drill stop on your drill.
If you drill deeper your could hit a water jacket in the head.

**Getter-Done** · 06-30-2018, 09:37 AM

https://www.homedepot.com/p/General-...FQOEaQodsA0Gqg Here is the link for the drill stop. It din't work in my first post.

**The Rocknrod** · 07-02-2018, 01:29 PM

I hear a heli-coil is stronger than the original hole. And that wood-pecker sticker? You need to send me that unit.

06-29-2018, 08:25 PM	#1
hevymetl Registered User Join Date: Jan 2016 Location: westchester ny Posts: 107	Exhaust/int. manifold bolt holes and muffler advice So I bought a new front pipe to replace old rusted one and while removing discovered the old exh manifold was cracked in several places and severely rusted. Ordered new one, installed, but discovered a couple of “soft” bolt holes thAt hold it on. What’s the best way to address this? Also, any advice on a good sounding muffler for this 250 6cyl, that’s readily available? P.O. had a canister looking one with a Toyota stamp on it. The ends are horribly disfigured from a crappy welding job and I’d just assume replace it. Thanks, John.

06-29-2018, 11:40 PM	#2
shp4man Registered User Join Date: Oct 2016 Location: San Diego, CA Posts: 557	Re: Exhaust/int. manifold bolt holes and muffler advice Not sure what soft bolt holes means- are they stripped? __________________ Everybody has to believe in something. I believe I'll have another beer.

06-30-2018, 08:22 AM	#3
hevymetl Registered User Join Date: Jan 2016 Location: westchester ny Posts: 107	Re: Exhaust/int. manifold bolt holes and muffler advice Yes. Script. I can get them pretty tight but if I go past a certain point it strips. I have the ones in question as tight as they will go and the truck actually runs pretty good with 0 exhaust leaks. Obviously it's not right but will do for now I guess. Just wondering what the best course of action was to remedy that situation. I'm still on the fence as to whether I'm going to pull it and replace it with a V8 but for now I just want to drive it.

06-30-2018, 08:54 AM	#4
vin63 It's Better With Nitro Join Date: Apr 2008 Location: Chino Hills, CA Posts: 2,262	Re: Exhaust/int. manifold bolt holes and muffler advice Are you referring to the threads in the cylinder head are stripped? Regarding a muffler, check in with a local exhaust/muffler shop and they should be able to steer you in the right direction for what you are wanting. I went with some Walker mufflers (galv. coated inside and out) on my Tempest and Riviera restorations since i wanted something really quiet. I run Borla mufflers on my hot rods. __________________ 1963 C-10: Deluxe-optioned cab, shortbed, fleetside Pontiac 462 ci, Kauffman D-Port alum. heads 4L80E, narrowed sheetmetal Ford 9-inch Tubular front and rear suspension Custom 6-piston front disc and 4-piston rear disc brakes Last edited by vin63; 06-30-2018 at 10:15 AM.

06-30-2018, 09:30 AM	#5
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 8,408	Re: Exhaust/int. manifold bolt holes and muffler advice If your going to swap the engine later these will repair your threads for awhile. https://www.autozone.com/test-scan-a...tem/557090_0_0 This Is just a 3/8 x 16tpi example. Make sure to get the correct size for your studs or bolts you are using. As I am not that familiar with a 6 cyl. Also if you attempt this make sure not to drill any deeper than the hole already are. Best way to do that is to put a drill stop on your drill. If you drill deeper your could hit a water jacket in the head. __________________ ________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build Last edited by Getter-Done; 06-30-2018 at 09:39 AM.

06-30-2018, 09:37 AM	#6
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 8,408	Re: Exhaust/int. manifold bolt holes and muffler advice https://www.homedepot.com/p/General-...FQOEaQodsA0Gqg Here is the link for the drill stop. It din't work in my first post. __________________ ________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build

07-02-2018, 01:29 PM	#7
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: Exhaust/int. manifold bolt holes and muffler advice I hear a heli-coil is stronger than the original hole. And that wood-pecker sticker? You need to send me that unit. __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?



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