BB Exhaust Manifolds - The 1947 - Present Chevrolet & GMC Truck Message Board Network

stope4 · 02-02-2009, 07:19 AM

Had an exhaust leak on the original manifolds. I removed them to see what was wrong. Turns out there were tons of other gaskets burned onto the surfaces. While removing the manifolds I noticed that one bolt on each side was missing. Cleaned them up and had the outer holes drilled out so I could make up the difference just in case the bolt was missing because the manifold had warped a little over the years. Now I'm trying to install the things and the same two bolts don't line up. While the manifolds are resting against the head you can see that over the years the ears have twisted ever so slightly. If I cinched the bolts the ears flush up real nice. I cannot seem to get these two bolts to grab thread. In each case the bolt I can't get in is on the outer end. On the left it's the rear bolt. On the right it's the front. Is there some kinda secret to installing these old manifolds? Any suggestions would be appreciated.

JimKshortstep4x4 · 02-02-2009, 08:41 AM

When the manifolds warp like that your options are pretty limited to replacing them. Having them machined so that the surface is flat and reaming the holes slightly oversize may help and could possibly work. The cost may be more then a set of good used ones.

My suggestion would be to replace them.

Jim

coggonobrien · 02-02-2009, 02:14 PM

edited by mod

stope4 · 02-02-2009, 09:05 PM

Gogginobrien, buying used ones leaves me with the feeling I would end up with a similar situation where the bolt holes don't line up. Has anyone ever placed a large pry bar between the two flanges and actually moved the flange in question?

I looked at most vendors. The only one showing new for sale is LMC. Is this my only option for new?

stope4 · 02-04-2009, 11:33 PM

Jim, when you say replace them, are you meaning with new or used? If new, do you know which vendors would sell them? I can't seem to find any who do.

tim21391 · 02-05-2009, 12:07 AM

my manifolds are going to become dust collectors in a few weeks.. i plan on buying headers at the swap meet im going to friday

**El Jay** · 02-05-2009, 01:38 AM

There's a handy, dandy little tool for spreading the runners on cast iron exhaust manifold, ever so slightly.You put it between the ports and slowly spreasd it, like a turnbuckle.

You have to go slow & easy to keep from cracking the manifold..I've only used mine on SBC's; I'm sure it would work on a BB.

I don't remember Ed Zachary where I got it; but I would imagine it was either CarQuest, or NAPA.

L.J.

**jerry moss** · 02-05-2009, 10:46 AM

definitly surface them ,open up all the holes and try the manifold spreaders. be very careful using the spreaders or you'll be buying new manifolds anyhow. i always enlarge all the bolt holes to 7/16 or 1/2 if there is enough material. clean the head real well and bolt them up metal to metal-no gasket-torque them down properly and you'll never have a problem.
trust me, it'll work fine- i've been working in the same muffler shop since feb. 1985 and thats how we do all of the older cast iron manifolds.

71 super · 02-05-2009, 03:09 PM

I ended up buy a set of repos for my bb because of the same type of issues. The repops are as heavy as original and worth the outlay of cash vs. trying to make 40 year old pieces work. I paid roughly $85 each for them. Also with factory manifolds it is not uncommon for the outer bolt hole to break out and leave you in a mess so if you use the spreaders be very careful.

70rs/ss · 02-05-2009, 04:13 PM

Here is a set from Rock auto, they are going to be about as much as a set of good headers, I'd do the headers if you are trying for the stock look, but that is me??

1977 CHEVROLET C10 PICKUP 7.4L 454cid V8 4BBL (S) : Exhaust : Exhaust Manifold Price Core Total
ATP Part # 101069 {Left Exhaust Manifold; Includes Necessary Hardware #343787}
Left

$79.79 $0.00 $79.79
DORMAN Part # 674159 {Original Equipment Solutions #12551444, 14103191, 343787}
Includes Gaskets and Hardware; Left

$85.79 $0.00 $85.79
DORMAN Part # 674244 {Original Equipment Solutions #10045732, 14048362, 6272280}
Includes Gaskets and Hardware; Right

$153.79 $0.00 $153.79

stope4 · 02-05-2009, 09:04 PM

Jerry, I thought about drilling all the holes but I had concerns about which bolts to use. What bolts do you use when you open the holes? Do you use the ones that have the flange on the head? Or do you use the ones without the flange but then use a flat washer and lock washer?

stope4 · 02-14-2009, 09:19 PM

O.k. got to work on the manifolds today. I got all the bolts in the left side. Took me damn near four hours and a lot of cussing under my breath but all the bolts are in. I used a large craftsman screwdriver. It's about 18 - 24 inches long. Bent the end thirty degrees but it was the only way to get all the bolts in. I even had my wonderful wife on Valentine's day out there pulling on the screwdriver with a cheater bar. Flat out brute force very carefully and all is well. Now for the right side.

02-02-2009, 08:41 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: BB Exhaust Manifolds When the manifolds warp like that your options are pretty limited to replacing them. Having them machined so that the surface is flat and reaming the holes slightly oversize may help and could possibly work. The cost may be more then a set of good used ones. My suggestion would be to replace them. Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

02-02-2009, 09:05 PM	#4
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	Re: BB Exhaust Manifolds Gogginobrien, buying used ones leaves me with the feeling I would end up with a similar situation where the bolt holes don't line up. Has anyone ever placed a large pry bar between the two flanges and actually moved the flange in question? I looked at most vendors. The only one showing new for sale is LMC. Is this my only option for new?

02-04-2009, 11:33 PM	#5
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	Re: BB Exhaust Manifolds Jim, when you say replace them, are you meaning with new or used? If new, do you know which vendors would sell them? I can't seem to find any who do.

02-05-2009, 12:07 AM	#6
tim21391 Registered User Join Date: Jul 2007 Location: Salina, Kansas Posts: 1,998	Re: BB Exhaust Manifolds my manifolds are going to become dust collectors in a few weeks.. i plan on buying headers at the swap meet im going to friday __________________ 1972 C-10...402/400..flowmaster 40 series 1967 Mustang 347 stroker/C-4 1966 Mustang 289/3-speed 2013 Mustang V6/6speed w/300 ponies I may be 23, but i sure do knows 67-72s are sexy! Its not MPG its smiles per gallon! build started 11/25/08 build thread: http://67-72chevytrucks.com/vboard/s....php?p=2993796

02-05-2009, 01:38 AM	#7
El Jay Gone to greener pastures Join Date: May 2007 Location: Gateway to the Delta Posts: 7,354	Re: BB Exhaust Manifolds There's a handy, dandy little tool for spreading the runners on cast iron exhaust manifold, ever so slightly.You put it between the ports and slowly spreasd it, like a turnbuckle. You have to go slow & easy to keep from cracking the manifold..I've only used mine on SBC's; I'm sure it would work on a BB. I don't remember Ed Zachary where I got it; but I would imagine it was either CarQuest, or NAPA. L.J. Attached Images __________________ '69 Chevy 1/2 T LWB Stepper: Daily Beater '72 GMC 3/4 T Fleet: Another Daily Beater '72 Plymouth Gran Coupe: ? "Ah women. They make the highs higher and the lows more frequent." Friedrich Nietzsche "Never kick a fresh turd on a hot day." Harry S. Truman GUN CONTROL: Never having to say, "I missed you." Always fire two warning shots into your attacker's chest area before putting a bullet between his eyes. Paraphrased from Louis Awerbuck

02-02-2009, 07:19 AM	#1
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	BB Exhaust Manifolds Had an exhaust leak on the original manifolds. I removed them to see what was wrong. Turns out there were tons of other gaskets burned onto the surfaces. While removing the manifolds I noticed that one bolt on each side was missing. Cleaned them up and had the outer holes drilled out so I could make up the difference just in case the bolt was missing because the manifold had warped a little over the years. Now I'm trying to install the things and the same two bolts don't line up. While the manifolds are resting against the head you can see that over the years the ears have twisted ever so slightly. If I cinched the bolts the ears flush up real nice. I cannot seem to get these two bolts to grab thread. In each case the bolt I can't get in is on the outer end. On the left it's the rear bolt. On the right it's the front. Is there some kinda secret to installing these old manifolds? Any suggestions would be appreciated.

02-02-2009, 02:14 PM	#3
coggonobrien Registered User Join Date: Mar 2008 Location: Coggon, IA Posts: 580	Re: BB Exhaust Manifolds edited by mod Last edited by Longhorn Man; 02-05-2009 at 05:22 PM.

02-05-2009, 10:46 AM	#8
jerry moss Born Psycho Join Date: Feb 2001 Location: brentwood,cal,usa Posts: 4,863	Re: BB Exhaust Manifolds definitly surface them ,open up all the holes and try the manifold spreaders. be very careful using the spreaders or you'll be buying new manifolds anyhow. i always enlarge all the bolt holes to 7/16 or 1/2 if there is enough material. clean the head real well and bolt them up metal to metal-no gasket-torque them down properly and you'll never have a problem. trust me, it'll work fine- i've been working in the same muffler shop since feb. 1985 and thats how we do all of the older cast iron manifolds. __________________ jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA

02-05-2009, 03:09 PM	#9
71 super Registered User Join Date: Sep 2005 Location: Canton North carolina Posts: 3,079	Re: BB Exhaust Manifolds I ended up buy a set of repos for my bb because of the same type of issues. The repops are as heavy as original and worth the outlay of cash vs. trying to make 40 year old pieces work. I paid roughly $85 each for them. Also with factory manifolds it is not uncommon for the outer bolt hole to break out and leave you in a mess so if you use the spreaders be very careful. __________________ 67 blue step side- bb 68 gold and white swb cst anniversary 68 custom swb hot rod Ls swap 69 swb cst 6 cylinder/ overdrive 69 black/black cst bb swb 70 orange and white cst Canada built truck swb bb 71 black and white super swb bb 71 red and white super swb 72 green and white super swb 4x4 62 nova wagon 400 series Ls swapped 68 Camaro 327/4 speed- 1 owner, original paint 66 Volkswagen bettle 69 auto stick Volkswagen Beetle

02-05-2009, 04:13 PM	#10
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,271	Re: BB Exhaust Manifolds Here is a set from Rock auto, they are going to be about as much as a set of good headers, I'd do the headers if you are trying for the stock look, but that is me?? 1977 CHEVROLET C10 PICKUP 7.4L 454cid V8 4BBL (S) : Exhaust : Exhaust Manifold Price Core Total ATP Part # 101069 {Left Exhaust Manifold; Includes Necessary Hardware #343787} Left $79.79 $0.00 $79.79 DORMAN Part # 674159 {Original Equipment Solutions #12551444, 14103191, 343787} Includes Gaskets and Hardware; Left $85.79 $0.00 $85.79 DORMAN Part # 674244 {Original Equipment Solutions #10045732, 14048362, 6272280} Includes Gaskets and Hardware; Right $153.79 $0.00 $153.79

02-05-2009, 09:04 PM	#11
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	Re: BB Exhaust Manifolds Jerry, I thought about drilling all the holes but I had concerns about which bolts to use. What bolts do you use when you open the holes? Do you use the ones that have the flange on the head? Or do you use the ones without the flange but then use a flat washer and lock washer?

02-14-2009, 09:19 PM	#12
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	Re: BB Exhaust Manifolds O.k. got to work on the manifolds today. I got all the bolts in the left side. Took me damn near four hours and a lot of cussing under my breath but all the bolts are in. I used a large craftsman screwdriver. It's about 18 - 24 inches long. Bent the end thirty degrees but it was the only way to get all the bolts in. I even had my wonderful wife on Valentine's day out there pulling on the screwdriver with a cheater bar. Flat out brute force very carefully and all is well. Now for the right side.



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