Replacing cracked exhaust manifold - The 1947 - Present Chevrolet & GMC Truck Message Board Network

KenL · 07-03-2005, 07:33 PM

Have a 79 4wd Blazer with mildly built 350, driver's side manifold is badly cracked. I'm considering replacing both manifolds with center dump rams horn style cause I hear they flow better. Anyone have any experience doing this in this vintage K5 ? Another alternative might be shorty headers if there are any affordable ones that fit, but I would prefer to keep a more "stock" look for now. TIA

71 shortbedfleetside · 07-04-2005, 12:19 AM

those center dump rams horn exh. man. always crack in the center because that's where all of the heat build up. what about smog legal headers?

longhorn71 · 07-04-2005, 01:05 AM

i have a set on my 81 2wd blazer and they are great!!The center dump ram horns flow way better then the newer ones too.As said above they do crack easily

KenL · 07-04-2005, 02:29 PM

Thanks for the replies. Smog legal headers would work for me, I just haven't found any that are listed as fitting this year Blazer and my current budget. I didn't know about the cracking issues in the rams horn manifolds. I guess I'll need to decide if I'm willing to take a chance on them while I save up for a nice set of headers. Nice to know they work well,though. I'm still worried about clearance issues in a 4wd vehicle. Anyone have any experience in that area?

kevinr1970 · 07-09-2005, 03:03 AM

Being in WA and the truck being a '79 you don't need to worry about smog legal.

Mad Dog · 07-24-2005, 06:03 AM

Just a thought..... try tig welding the manifolds, I tigged the pass side manifold 3 years ago. Any half ass decent tig guy should be able to do it. I used alot of heat and nickel rod.

KenL · 07-25-2005, 02:09 AM

That would have been too simple, Mad Dog! Being a firm believer in making small projects into major ordeals, I found a pair of rams horns at the local junkyard. I got them looking real purty and installed them this week. Spent all weekend trying to make the old set of plug wires fit (they won't), and modifying the old exhaust system to fit (it won't). Local muffler shops won't touch it because its not emissions legal. Part of the fun of modifying is solving a dilemma, but until you find the solution its a real PITA sometimes.

07-03-2005, 07:33 PM	#1
KenL Registered User Join Date: Jun 2005 Location: Washington Posts: 3	Replacing cracked exhaust manifold Have a 79 4wd Blazer with mildly built 350, driver's side manifold is badly cracked. I'm considering replacing both manifolds with center dump rams horn style cause I hear they flow better. Anyone have any experience doing this in this vintage K5 ? Another alternative might be shorty headers if there are any affordable ones that fit, but I would prefer to keep a more "stock" look for now. TIA

07-09-2005, 03:03 AM	#5
kevinr1970 Senior Member Join Date: Aug 2004 Location: Everett, WA Posts: 2,316	Being in WA and the truck being a '79 you don't need to worry about smog legal. __________________ 2009 Honda Fit CfC (bsf 44.9 mpg) 2000 Tahoe Limited 1991 GMC CrewCab Dually 2wd, will end up swb, not dually and replace CCswb below 1991 GMC CrewCab Dually 4x4, just going to fix things up for now 1982/1989 K5/GMC Jimmy 2wd 1987 GMC 1/2 ton swb 2wd Crew (sold)

07-24-2005, 06:03 AM	#6
Mad Dog Registered User Join Date: Jun 2005 Location: Independence MO Posts: 87	Just a thought..... try tig welding the manifolds, I tigged the pass side manifold 3 years ago. Any half ass decent tig guy should be able to do it. I used alot of heat and nickel rod. __________________ 72 C10 longbed 5/7 drop, Telstars, 350/th400(for now) 69 Chevelle SS396 (427/th400) 88 K5 on 35's (355/700R4/208)

07-04-2005, 12:19 AM	#2
71 shortbedfleetside Registered User Join Date: Jun 2005 Location: Simi Valley, Ca. Posts: 351	those center dump rams horn exh. man. always crack in the center because that's where all of the heat build up. what about smog legal headers?

07-04-2005, 01:05 AM	#3
longhorn71 Senior Member Join Date: Sep 2004 Location: CANADA Posts: 1,681	i have a set on my 81 2wd blazer and they are great!!The center dump ram horns flow way better then the newer ones too.As said above they do crack easily

07-04-2005, 02:29 PM	#4
KenL Registered User Join Date: Jun 2005 Location: Washington Posts: 3	Thanks for the replies. Smog legal headers would work for me, I just haven't found any that are listed as fitting this year Blazer and my current budget. I didn't know about the cracking issues in the rams horn manifolds. I guess I'll need to decide if I'm willing to take a chance on them while I save up for a nice set of headers. Nice to know they work well,though. I'm still worried about clearance issues in a 4wd vehicle. Anyone have any experience in that area?

07-25-2005, 02:09 AM	#7
KenL Registered User Join Date: Jun 2005 Location: Washington Posts: 3	That would have been too simple, Mad Dog! Being a firm believer in making small projects into major ordeals, I found a pair of rams horns at the local junkyard. I got them looking real purty and installed them this week. Spent all weekend trying to make the old set of plug wires fit (they won't), and modifying the old exhaust system to fit (it won't). Local muffler shops won't touch it because its not emissions legal. Part of the fun of modifying is solving a dilemma, but until you find the solution its a real PITA sometimes.



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