Need opinions on exhaust manifolds. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

DT1 · 10-10-2010, 11:28 AM

One of my exhaust manifolds is cracked and I'm looking for a new set. The truck is 71 C10 350 with 70 heads.
Anyone have opinions on aftermarket (LMC) or should I look for original?

LandonL · 10-10-2010, 11:48 AM

Unrelated to your specific application, I ordered a 250 6 cyl exhaust manifold from them. It was an "OEM" part as stamped in the casting. Looked to be of good quality, and bolted right up and fit perfectly considering the 6cyl's exhaust manifold mates to the intake. It mated to an original intake no problem, considering the manifolds your going to buy will most likely be cast by the same company I should see you having no problems. Maybe someone who actually bought those specific ones will comment.

ChevLoRay · 10-10-2010, 12:05 PM

Here's a pic of a factory left side manifold. But, I'd also check out Summit Racings' brand of headers. They have the same part number base as Flow Tech, so it's kinda easy to see where they're from.

llowlife · 10-10-2010, 12:44 PM

I have about 15 -20 sets of "originals" I have been toying with sandblasting and painting. The problem with the originals is I have found some of the used ones have shrunk the outside ports and you can have a heck of a time getting that final bolt in straight. If you can find a good price I might say go with the new ones if the quality is there. By the time you get them blasted and painted I wonder how far you would be ahead?

DT1 · 10-10-2010, 01:27 PM

Quote:

Originally Posted by llowlife

I have about 15 -20 sets of "originals" I have been toying with sandblasting and painting. The problem with the originals is I have found some of the used ones have shrunk the outside ports and you can have a heck of a time getting that final bolt in straight. If you can find a good price I might say go with the new ones if the quality is there. By the time you get them blasted and painted I wonder how far you would be ahead?

I found one on Ebay. The casting numbers are different but they look identical. Do you know if they interchange? My casting 3932478 Ebay casting 3832473

Notrodder · 10-10-2010, 02:10 PM

[QUOTE=llowlife;4233345]The problem with the originals is I have found some of the used ones have shrunk the outside ports and you can have a heck of a time getting that final bolt in straight.[QUOTE]

You can make a tool that will spread them, enough for the outside bolts to line up, out of common hardware. I'll try to post pics, unless someone beats me to it.

llowlife · 10-10-2010, 06:29 PM

Just looked at your ebay number. Yeah it will fit yours providing you don't have any auxiliary holes in the front like the one pic'ed above. 50.00 seems kinda high to me though I have no idea what they go for anymore. If I get to my shop tonight I will pull my master parts catalog out and blow the dust off to check numbers.

10-10-2010, 11:28 AM	#1
DT1 Registered User Join Date: Oct 2009 Location: Gardnerville Nv No Mo Cali!! Posts: 869	Need opinions on exhaust manifolds. One of my exhaust manifolds is cracked and I'm looking for a new set. The truck is 71 C10 350 with 70 heads. Anyone have opinions on aftermarket (LMC) or should I look for original?

10-10-2010, 11:48 AM	#2
LandonL Registered User Join Date: Nov 2009 Location: Georgia Posts: 440	Re: Need opinions on exhaust manifolds. Unrelated to your specific application, I ordered a 250 6 cyl exhaust manifold from them. It was an "OEM" part as stamped in the casting. Looked to be of good quality, and bolted right up and fit perfectly considering the 6cyl's exhaust manifold mates to the intake. It mated to an original intake no problem, considering the manifolds your going to buy will most likely be cast by the same company I should see you having no problems. Maybe someone who actually bought those specific ones will comment. __________________ ---\| 1967 GMC Stepside \|-- 250 L6 .030 over ---\| 1985 Porsche 944/1 \|--- Build Thread: '67 GMC http://67-72chevytrucks.com/vboard/s...d.php?t=378640

10-10-2010, 12:05 PM	#3
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: Need opinions on exhaust manifolds. Here's a pic of a factory left side manifold. But, I'd also check out Summit Racings' brand of headers. They have the same part number base as Flow Tech, so it's kinda easy to see where they're from. Attached Images __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

10-10-2010, 12:44 PM	#4
llowlife Registered User Join Date: Jan 2010 Location: Elgin Mn Posts: 112	Re: Need opinions on exhaust manifolds. I have about 15 -20 sets of "originals" I have been toying with sandblasting and painting. The problem with the originals is I have found some of the used ones have shrunk the outside ports and you can have a heck of a time getting that final bolt in straight. If you can find a good price I might say go with the new ones if the quality is there. By the time you get them blasted and painted I wonder how far you would be ahead? __________________ In the beginning of a change, the patriot is a scarce man, brave hated and scorned. When his cause succeeds however, the timid join him , for then it costs nothing to be a patriot. I am a revolutionary...so my son can be a farmer...so his son can be a poet. If there must be trouble, let it be in my day, so my child may have peace... 72 short step w/ 388 /4l80e/ and 3.08 gears.

10-10-2010, 02:10 PM	#6
Notrodder Registered User Join Date: Jun 2010 Location: Lompoc, CA Posts: 104	Re: Need opinions on exhaust manifolds. [QUOTE=llowlife;4233345]The problem with the originals is I have found some of the used ones have shrunk the outside ports and you can have a heck of a time getting that final bolt in straight.[QUOTE] You can make a tool that will spread them, enough for the outside bolts to line up, out of common hardware. I'll try to post pics, unless someone beats me to it. Last edited by Notrodder; 10-10-2010 at 02:11 PM.

10-10-2010, 06:29 PM	#7
llowlife Registered User Join Date: Jan 2010 Location: Elgin Mn Posts: 112	Re: Need opinions on exhaust manifolds. Just looked at your ebay number. Yeah it will fit yours providing you don't have any auxiliary holes in the front like the one pic'ed above. 50.00 seems kinda high to me though I have no idea what they go for anymore. If I get to my shop tonight I will pull my master parts catalog out and blow the dust off to check numbers. __________________ In the beginning of a change, the patriot is a scarce man, brave hated and scorned. When his cause succeeds however, the timid join him , for then it costs nothing to be a patriot. I am a revolutionary...so my son can be a farmer...so his son can be a poet. If there must be trouble, let it be in my day, so my child may have peace... 72 short step w/ 388 /4l80e/ and 3.08 gears.

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