Best option for inline 6 exhaust manifold - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**HeloCrewChief** · 03-06-2026, 08:49 AM

My 68 50th short bed needs an exhaust manifold. What is the best option out there? Skeptical of old used and the Chinese aftermarket ones. Seeing what way is the best option. I love my stock inline 6 and three on the tree set up as it’s different than all my other stuff and runs like a sewing machine. Not looking to do a header or anything like that.

**70STOVEBOLT** · 03-06-2026, 02:58 PM

I know you said you didn’t want used but your best bet is a used 292 manifold, it has a larger outlet.

truckster · 03-06-2026, 03:32 PM

Quote:

Originally Posted by 70STOVEBOLT

I know you said you didn’t want used but your best bet is a used 292 manifold, it has a larger outlet.

I agree. Your options are limited.

**HeloCrewChief** · 03-06-2026, 04:42 PM

Right on. Just worried I’ll get an original one and it cracks again. I’ve had more than a few cracked exhaust manifolds on different trucks over the years. Worse one was a 1991 V3500 with the TBI 454. Just curious if the reproduction ones are decent.

**PbFut** · 03-08-2026, 10:21 AM

Is your timing off and over heating the manifold? Given poor selection of available replacement, is the crack in a repairable location?. Remove for prep, Drill each end of crack to contain it from running. V grind, reinstall, heat cycle a few times. Retorque, clean, then weld while warm.

**Jason Banks** · 03-08-2026, 09:03 PM

I have used a China one with good results. I have several of the original style and they all have the shaft for the flapper flopping around so they would leak exhaust gas out around the shaft. Not to mention all the springs are shot.

If you get a China one, just make sure it is flat. I also took a die grinder to the one I used and cleaned up some particularly rough areas and extra material.

**Steeveedee** · 03-08-2026, 09:08 PM

Yup, making sure it is flat is very important. I've assaulted exhaust manifolds with a straight bar and a mill file. It can be very time consuming, but if the manifold lays flat on the head, the stress and possible subsequent cracking are greatly reduced.

1964FarmFreshC10 · 03-13-2026, 03:52 PM

Get the cast manifolds from 12bolt.

https://www.12bolt.com/store/p153/Ex...0-250-292.html

**MikeB** · 03-13-2026, 07:31 PM

Quote:

Originally Posted by 1964FarmFreshC10

Get the cast manifolds from 12bolt.

https://www.12bolt.com/store/p153/Ex...0-250-292.html

That's pretty cool! Reminds me of Fenton split manifolds for the 235.

Rock Auto shows an imported manifold for the 250. Part number ATP 101140.

I ran a set of Chinese manifolds on my truck's 350 for around 12 years. They never leaked, and when I removed them to install headers there were no signs of cracks.

**Palf70Step** · 03-14-2026, 07:33 AM

Quote:

Originally Posted by 1964FarmFreshC10

Get the cast manifolds from 12bolt.

https://www.12bolt.com/store/p153/Ex...0-250-292.html

Definitely the way to go. They make good sound too!

**'68OrangeSunshine** · 03-15-2026, 10:00 PM

Clifford and Offenhauser both make [made?] aftermarket L6 intakes.

I have an Offy intake and Clifford headers. New in 1977. Still good. Still running.
Pace and Hedman make L6 headers, too.
If you're searching junkyards for the HD 292 GM exhaust, they are on the bigger trucks that were optioned L25 [292]. Best ''tell' is the THREE [not two] exhaust pipe mating studs.

KQQL IT · 03-16-2026, 08:52 AM

https://www.12bolt.com/store/p153/Ex...0-250-292.html

My brother's 56 with a 235-5 speed sounds awesome with a split manifold and a pair glass packs

03-06-2026, 08:49 AM	#1
HeloCrewChief Senior Member Join Date: Aug 2010 Location: North Alabama Posts: 1,066	Best option for inline 6 exhaust manifold My 68 50th short bed needs an exhaust manifold. What is the best option out there? Skeptical of old used and the Chinese aftermarket ones. Seeing what way is the best option. I love my stock inline 6 and three on the tree set up as it’s different than all my other stuff and runs like a sewing machine. Not looking to do a header or anything like that. Attached Images __________________ 1970 C10 to K20 conversion 1974 GMC Jimmy 1968 50th Anniversary Short Bed 1968 Chevelle 1964 Comet Caliente 1990 W250 Cummins

03-06-2026, 02:58 PM	#2
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 7,062	Re: Best option for inline 6 exhaust manifold I know you said you didn’t want used but your best bet is a used 292 manifold, it has a larger outlet. __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear

03-06-2026, 04:42 PM	#4
HeloCrewChief Senior Member Join Date: Aug 2010 Location: North Alabama Posts: 1,066	Re: Best option for inline 6 exhaust manifold Right on. Just worried I’ll get an original one and it cracks again. I’ve had more than a few cracked exhaust manifolds on different trucks over the years. Worse one was a 1991 V3500 with the TBI 454. Just curious if the reproduction ones are decent. __________________ 1970 C10 to K20 conversion 1974 GMC Jimmy 1968 50th Anniversary Short Bed 1968 Chevelle 1964 Comet Caliente 1990 W250 Cummins

03-08-2026, 10:21 AM	#5
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 1,024	Re: Best option for inline 6 exhaust manifold Is your timing off and over heating the manifold? Given poor selection of available replacement, is the crack in a repairable location?. Remove for prep, Drill each end of crack to contain it from running. V grind, reinstall, heat cycle a few times. Retorque, clean, then weld while warm.

03-08-2026, 09:03 PM	#6
Jason Banks Senior Member Join Date: Dec 1999 Location: TX Posts: 1,787	Re: Best option for inline 6 exhaust manifold I have used a China one with good results. I have several of the original style and they all have the shaft for the flapper flopping around so they would leak exhaust gas out around the shaft. Not to mention all the springs are shot. If you get a China one, just make sure it is flat. I also took a die grinder to the one I used and cleaned up some particularly rough areas and extra material.

03-08-2026, 09:08 PM	#7
Steeveedee Ram-A-Lam-A-Ding-Dong Join Date: Jan 2013 Location: Simi Valley, CA Posts: 11,899	Re: Best option for inline 6 exhaust manifold Yup, making sure it is flat is very important. I've assaulted exhaust manifolds with a straight bar and a mill file. It can be very time consuming, but if the manifold lays flat on the head, the stress and possible subsequent cracking are greatly reduced. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

03-13-2026, 03:52 PM	#8
1964FarmFreshC10 Registered User Join Date: Mar 2025 Location: Shelburne, Ontario Posts: 125	Re: Best option for inline 6 exhaust manifold Get the cast manifolds from 12bolt. https://www.12bolt.com/store/p153/Ex...0-250-292.html

03-15-2026, 10:00 PM	#11
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 8,115	Re: Best option for inline 6 exhaust manifold Clifford and Offenhauser both make [made?] aftermarket L6 intakes. I have an Offy intake and Clifford headers. New in 1977. Still good. Still running. Pace and Hedman make L6 headers, too. If you're searching junkyards for the HD 292 GM exhaust, they are on the bigger trucks that were optioned L25 [292]. Best ''tell' is the THREE [not two] exhaust pipe mating studs. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

03-16-2026, 08:52 AM	#12
KQQL IT At the body shop. Join Date: Aug 2009 Location: Land of fruits and nuts. Posts: 5,447	Re: Best option for inline 6 exhaust manifold https://www.12bolt.com/store/p153/Ex...0-250-292.html My brother's 56 with a 235-5 speed sounds awesome with a split manifold and a pair glass packs __________________ " That didnt make it any newer " " Dont antique the equipment "



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