Can 2.5 center drop manifolds be used on a SBC 2wd? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chewychevy67 · 11-15-2018, 01:33 PM

My 327 engine build has changed direction a bit and now I'm looking to do something a little more peppy. That being said I need more breathing. Any of you guys successfully used 2.5" ramhorns on your 67 72 2wd trucks? Any starter issues? Post pictures if you have please?

**Grumpy old man** · 11-15-2018, 02:38 PM

I am ,There is plenty of room these are 2 1/2 " . You'll have to take it to a muffler shop for pipes I'm sure there is no kit that would bolt up , this is with the engine bolted into the front 350 position Not sure about if it was bolted into the L6 spot ?

chewychevy67 · 11-15-2018, 02:42 PM

I am having a whole new exhaust put on at a shop so that's not an issue. I see that's a 67 frame too just like mine. That's good to know. Thanks for the pics

chewychevy67 · 11-20-2018, 11:27 AM

Next question is will I be ok if I drop from 2.5 manifolds to 2.25 pipes? I was initially going to run stock 2" manifolds and go to 2.25"pipe but not sure if I want to choke it out the manifold. I really don't want 2.5"pipes all the way back. Guess I should add that my 327 will Be running aprox 330 hp at the flywheel.

Mike C · 11-20-2018, 03:10 PM

Why not go 2 1/2" all the way?

Your motor is approximately the same setup I have in my Jimmy. .030 327 with forged pistons using a large journal crank in a 4 bolt 350 block. 64cc heads so about 9.5:1 compression. Crane Energizer 266 cam (210 @ .050 .440 lift). Weiand 8004 intake with a JET stage II Q-jet and a small cap MSD ready to run distributor.

I replaced a set of Heddman headers, 2 1/4" exhaust system and some cheapie turbo mufflers with teh 2 1/2" 'vette manifolds, 2 1/2" system that exits 45 degrees to the frame past the rear tires and used the Hemi Turbo mufflers from Dynomax with the 20" case.

Not only is it quieter, It may have even picked up some low end power with no fall-off up high.

chewychevy67 · 11-20-2018, 03:22 PM

Because I have my exhaust pretty much ready to put on. I just bought some 2.5" manifolds because the guy building my engine recommended it over 2" but it wasn't necessary just my call in case I decide to add to my engine in the future. I was thinking 2.25" to keep noise down. At least after the mufflers.

chewychevy67 · 01-28-2019, 11:16 PM

Hey for you who have Done this did you use a mini starter or a stock size one? Also how hard is it to get to?

shoveldug · 01-29-2019, 07:26 AM

Quote:

Originally Posted by chewychevy67

Hey for you who have Done this did you use a mini starter or a stock size one? Also how hard is it to get to?

Stock starter..............plenty of room

chewychevy67 · 01-29-2019, 10:17 AM

Great. I didn't want to buy a new mini starter. Mine is all rebuilt and ready to go. If I had to go that way I would consider going back to the original angled horns.

OregonNed · 01-29-2019, 11:23 AM

This is an interesting read on manifold that straight drop in a '68, which should be the same as the '67. I was curious about clearance too, and also contacted the author to confirm. For what its worth.

https://www.hotrod.com/articles/1112...engine-exhaust

11-15-2018, 01:33 PM	#1
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,454	Can 2.5 center drop manifolds be used on a SBC 2wd? My 327 engine build has changed direction a bit and now I'm looking to do something a little more peppy. That being said I need more breathing. Any of you guys successfully used 2.5" ramhorns on your 67 72 2wd trucks? Any starter issues? Post pictures if you have please?

11-15-2018, 02:38 PM	#2
Grumpy old man Senior Member Join Date: Dec 2013 Location: Gods country East,Tn Posts: 8,545	Re: Can 2.5 center drop manifolds be used on a SBC 2wd? I am ,There is plenty of room these are 2 1/2 " . You'll have to take it to a muffler shop for pipes I'm sure there is no kit that would bolt up , this is with the engine bolted into the front 350 position Not sure about if it was bolted into the L6 spot ? Attached Images __________________ 1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop

11-15-2018, 02:42 PM	#3
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,454	Re: Can 2.5 center drop manifolds be used on a SBC 2wd? I am having a whole new exhaust put on at a shop so that's not an issue. I see that's a 67 frame too just like mine. That's good to know. Thanks for the pics

11-20-2018, 11:27 AM	#4
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,454	Re: Can 2.5 center drop manifolds be used on a SBC 2wd? Next question is will I be ok if I drop from 2.5 manifolds to 2.25 pipes? I was initially going to run stock 2" manifolds and go to 2.25"pipe but not sure if I want to choke it out the manifold. I really don't want 2.5"pipes all the way back. Guess I should add that my 327 will Be running aprox 330 hp at the flywheel.

11-20-2018, 03:10 PM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,715	Re: Can 2.5 center drop manifolds be used on a SBC 2wd? Why not go 2 1/2" all the way? Your motor is approximately the same setup I have in my Jimmy. .030 327 with forged pistons using a large journal crank in a 4 bolt 350 block. 64cc heads so about 9.5:1 compression. Crane Energizer 266 cam (210 @ .050 .440 lift). Weiand 8004 intake with a JET stage II Q-jet and a small cap MSD ready to run distributor. I replaced a set of Heddman headers, 2 1/4" exhaust system and some cheapie turbo mufflers with teh 2 1/2" 'vette manifolds, 2 1/2" system that exits 45 degrees to the frame past the rear tires and used the Hemi Turbo mufflers from Dynomax with the 20" case. Not only is it quieter, It may have even picked up some low end power with no fall-off up high. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

11-20-2018, 03:22 PM	#6
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,454	Re: Can 2.5 center drop manifolds be used on a SBC 2wd? Because I have my exhaust pretty much ready to put on. I just bought some 2.5" manifolds because the guy building my engine recommended it over 2" but it wasn't necessary just my call in case I decide to add to my engine in the future. I was thinking 2.25" to keep noise down. At least after the mufflers.

01-28-2019, 11:16 PM	#7
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,454	Re: Can 2.5 center drop manifolds be used on a SBC 2wd? Hey for you who have Done this did you use a mini starter or a stock size one? Also how hard is it to get to? Last edited by chewychevy67; 01-29-2019 at 12:23 AM.

01-29-2019, 10:17 AM	#9
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,454	Re: Can 2.5 center drop manifolds be used on a SBC 2wd? Great. I didn't want to buy a new mini starter. Mine is all rebuilt and ready to go. If I had to go that way I would consider going back to the original angled horns.

01-29-2019, 11:23 AM	#10
OregonNed Registered User Join Date: Dec 2012 Location: Vancouver, Washington Posts: 1,644	Re: Can 2.5 center drop manifolds be used on a SBC 2wd? This is an interesting read on manifold that straight drop in a '68, which should be the same as the '67. I was curious about clearance too, and also contacted the author to confirm. For what its worth. https://www.hotrod.com/articles/1112...engine-exhaust __________________ 1968 Chevrolet C/10 LWB - 327, TH350 - 4/5 Drop



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