Exhaust Manifold Bolts - The 1947 - Present Chevrolet & GMC Truck Message Board Network

LSUMurse · 12-13-2013, 07:36 PM

Is there anything special about them? I'm putting in a new engine and was planning on reusing the old ones, but they are pretty well rusted, so I want to replace them.

Are they grade 5, grade 8, something else?

It's a stock manifold on a stock 307.

Thanks in advance.

billnorman · 12-13-2013, 07:45 PM

I could be wrong, but if you do replace the bolts, if they are bolts, I'd use grade 5 or better and coat them with anti-sieze. I'd use a tap or thread chaser in the old holes to make sure there was no flakes left to gall the new bolts. If they are studs I think I'd use brass nuts. That advice is probably worth what it costs, it's free.

LSUMurse · 12-13-2013, 07:50 PM

One of the old ones for reference.

tlcrz1972 · 12-13-2013, 08:29 PM

I've re-used the manifold bolts many times over, and have had minimal issues.

I pick out the best ones from my selection and put new lock washers on them. I I have never used any anti-seize on them.

1972SUPERSB · 12-13-2013, 11:27 PM

I used grade 8 bolts but I'm pretty sure grade 5 was stock. There is no reason in my mind to use the old bolts. Just buy new ones with lock washers. You might spend $10. Worth every penny. The old ones are rusted, weak and worn.

Bigdav160 · 12-14-2013, 12:05 AM

I seem to remember the length was something like 2 3/4" which isn't usually found at the local BORG.

NC_John · 12-14-2013, 02:53 PM

Quote:

Originally Posted by Bigdav160

I seem to remember the length was something like 2 3/4" which isn't usually found at the local BORG.

I had to get them from the dealer. Regular over-the-counter bolts are either a tick too long or a tick too short.

MARKDTN · 12-16-2013, 01:48 PM

If you have a Caterpillar dealer nearby, they have nice GR8 case-hardened bolts in 1/4" increments so you can find the 2 3/4" long. You might get them in GR8 at Lowes or GR5 or 8 at a bolt store in a larger city.

Longhorn 70 · 12-16-2013, 05:01 PM

Ace Hardware is your friend. If there is one near by, give them a try.

67_C20Pres · 12-16-2013, 05:42 PM

I've bought all kinds of stuff from McMaster-Carr for many projects throughout the years. They have lots of stuff you won't find elsewhere and usually their shipping is fast. Huge catalog that has ended up as a "sit down reading material book".

http://www.mcmaster.com/#

BB72CHEVKT · 12-16-2013, 05:53 PM

I got stainless ones from Fastenal and I have 11k miles and no leaks.

PatrickGMC70 · 12-22-2013, 10:53 PM

I would definitely replace them. The chance of an old bolt snapping off in the head makes it an easy decision for me. Those bolts see a lot of heat cycles.

I have factory air, so my truck has 3 or 4 different size bolts. I think I ordered them from Brothers or Classic Industries; can't remember for sure. I used anti-seize.

On the 350, the torque spec was different for the inside bolts. Not sure if it's the same for the 307.

**Zeke's Garage** · 12-23-2013, 09:20 AM

Quote:

Originally Posted by BB72CHEVKT

I got stainless ones from Fastenal and I have 11k miles and no leaks.

+1 on That.. I tend to replace all the hardware in the engine compartment with cap head stainless hardware from Fastenal. I also tend to use copper anti-seize on any dissimilar metals, especially when going into aluminum.

Andy4639 · 12-23-2013, 12:47 PM

It's always good to use new bolting material when you can and always put anti seize on any bolt threads, flat of head and on the flat washers. No need to put it on lock washers though.
Grade 8 is over kill for this app., grade 5 may even be a little over kill.This isn't holding anything that would cause bodly damage if it broke.

12-13-2013, 07:36 PM	#1
LSUMurse Registered User Join Date: Mar 2012 Location: New Orleans, La Posts: 406	Exhaust Manifold Bolts Is there anything special about them? I'm putting in a new engine and was planning on reusing the old ones, but they are pretty well rusted, so I want to replace them. Are they grade 5, grade 8, something else? It's a stock manifold on a stock 307. Thanks in advance. __________________ It's not that I am apathetic, I just don't care. If your life is a joke, it appears death will be your punchline.

12-13-2013, 07:45 PM	#2
billnorman Registered User Join Date: Mar 2009 Location: glen burnie md Posts: 174	Re: Exhaust Manifold Bolts I could be wrong, but if you do replace the bolts, if they are bolts, I'd use grade 5 or better and coat them with anti-sieze. I'd use a tap or thread chaser in the old holes to make sure there was no flakes left to gall the new bolts. If they are studs I think I'd use brass nuts. That advice is probably worth what it costs, it's free.

12-13-2013, 07:50 PM	#3
LSUMurse Registered User Join Date: Mar 2012 Location: New Orleans, La Posts: 406	Re: Exhaust Manifold Bolts One of the old ones for reference. Attached Images __________________ It's not that I am apathetic, I just don't care. If your life is a joke, it appears death will be your punchline.

12-13-2013, 08:29 PM	#4
tlcrz1972 Registered User Join Date: Apr 2013 Location: Gainesville, TEXAS Posts: 658	Re: Exhaust Manifold Bolts I've re-used the manifold bolts many times over, and have had minimal issues. I pick out the best ones from my selection and put new lock washers on them. I I have never used any anti-seize on them. __________________ 1972 Chevrolet Cheyenne LB 1/2 ton finished restoration/rebuild 1995 350 throttle body FI, 4L6E (running on modified GM wiring harness) 3.08 posi rearend, factory A/C on 134A, p/s, p/b, late 70's power windows and locks and cruise, speakers in the dash + 6x9's behind the seat, factory tilt, 40 gallon fuel tank in the bed with integrated tool box, air assist bags on the rearend, sway bar up front and much more. 1972 chevrolet SNB finished 2002, 350 TB FI, TH400, factory A/C, p/b, p/s, (FOR SALE) 1969 Chevrolet 1 ton in work, home made PTO dump bed extended frame, 350 CI , 1972 Chevrolet 3/4 ton suburban future project 1972 Chevrolet 3/4 ton p/u maybe a project one day 1966 Toyota Landcruiser my playtoy

12-13-2013, 11:27 PM	#5
1972SUPERSB Registered User Join Date: Sep 2012 Location: San Antonio, TX Posts: 1,026	Re: Exhaust Manifold Bolts I used grade 8 bolts but I'm pretty sure grade 5 was stock. There is no reason in my mind to use the old bolts. Just buy new ones with lock washers. You might spend $10. Worth every penny. The old ones are rusted, weak and worn. __________________ Jeff 1972 Cheyenne Super SWB 350, Auto, Bucket Seats w/Console, Tach, Factory A/C, P/S ,P/B, Tilt 1998 Chevy 1500 Ext Cab 5.7, Pewter w/blue interior

12-14-2013, 12:05 AM	#6
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: Exhaust Manifold Bolts I seem to remember the length was something like 2 3/4" which isn't usually found at the local BORG. __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe

12-16-2013, 01:48 PM	#8
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,157	Re: Exhaust Manifold Bolts If you have a Caterpillar dealer nearby, they have nice GR8 case-hardened bolts in 1/4" increments so you can find the 2 3/4" long. You might get them in GR8 at Lowes or GR5 or 8 at a bolt store in a larger city. __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project

12-16-2013, 05:01 PM	#9
Longhorn 70 Registered User Join Date: Dec 2012 Location: Chandler AZ Posts: 1,149	Re: Exhaust Manifold Bolts Ace Hardware is your friend. If there is one near by, give them a try. __________________ 1970 Longhorn, Front Disc, 350/4 bolt, 882 heads, HEI, Edelbrock, 700R4, HO-52/4.11. 1996 Corvette, Collector Roadster, LT4, 396, 450RWHP, 6sp, 4.11/Dana44/posi 5 point roll bar And let us not grow weary of doing good, for in due season we will reap, if we do not give up. Gal 6:9

12-16-2013, 05:42 PM	#10
67_C20Pres New Member Join Date: May 2007 Location: Las Vegas Posts: 33	Re: Exhaust Manifold Bolts I've bought all kinds of stuff from McMaster-Carr for many projects throughout the years. They have lots of stuff you won't find elsewhere and usually their shipping is fast. Huge catalog that has ended up as a "sit down reading material book". http://www.mcmaster.com/# __________________ Steve 67' C20 - Newest - My junkyard dog and work in progress

12-16-2013, 05:53 PM	#11
BB72CHEVKT Junior Member Join Date: Mar 2007 Location: Hideaway, TX Posts: 4,950	Re: Exhaust Manifold Bolts I got stainless ones from Fastenal and I have 11k miles and no leaks. __________________ 71 Suburban 350/700R4 Project Trixie 72 CHEVY,Highlander,SWB,396,T400

12-22-2013, 10:53 PM	#12
PatrickGMC70 Registered User Join Date: Jun 2010 Location: Parkville, MD Posts: 163	Re: Exhaust Manifold Bolts I would definitely replace them. The chance of an old bolt snapping off in the head makes it an easy decision for me. Those bolts see a lot of heat cycles. I have factory air, so my truck has 3 or 4 different size bolts. I think I ordered them from Brothers or Classic Industries; can't remember for sure. I used anti-seize. On the 350, the torque spec was different for the inside bolts. Not sure if it's the same for the 307.

12-23-2013, 12:47 PM	#14
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Exhaust Manifold Bolts It's always good to use new bolting material when you can and always put anti seize on any bolt threads, flat of head and on the flat washers. No need to put it on lock washers though. Grade 8 is over kill for this app., grade 5 may even be a little over kill.This isn't holding anything that would cause bodly damage if it broke. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.



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