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01-29-2011, 02:08 AM | #1 | |
But Found Her 25yrs Later!
Join Date: Oct 2010
Location: Oregon City, Oregon
Posts: 10,526
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Re: Headers to 2.5" Ramhorns
Ok, I found the answer:
Quote:
http://67-72chevytrucks.com/vboard/s...d.php?t=404828 The left (Driver's side) doesn't have the 'heat tube'
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I lost my 65 - Found it 25 years later: http://67-72chevytrucks.com/vboard/s...d.php?t=426650 66 C20 Service Truck: http://67-72chevytrucks.com/vboard/s...d.php?t=428035 |
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01-29-2011, 01:44 AM | #2 |
But Found Her 25yrs Later!
Join Date: Oct 2010
Location: Oregon City, Oregon
Posts: 10,526
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Re: Headers to 2.5" Ramhorns
RockAuto has them for $47.79 for either the DOR-674-504 or DOR-674-503.
They add $8 each for shipping. Amazon has the 504s for 55.94 with free shipping. but if you got two rights from amazon, you could have two 503s to your doorstep for $98.40
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I lost my 65 - Found it 25 years later: http://67-72chevytrucks.com/vboard/s...d.php?t=426650 66 C20 Service Truck: http://67-72chevytrucks.com/vboard/s...d.php?t=428035 Last edited by LostMy65; 01-29-2011 at 02:17 AM. |
03-09-2011, 01:43 AM | #3 |
Collector of Projects
Join Date: Apr 2003
Location: Las Vegas
Posts: 3,106
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Re: Headers to 2.5" Ramhorns
another alternative....
http://www.jegs.com/i/Wysco/938/MA035RAW/10002/-1 |
03-09-2011, 06:24 AM | #4 |
Rottenwood Garage Member
Join Date: May 2005
Location: Marietta, Georgia
Posts: 4,321
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Re: Headers to 2.5" Ramhorns
I just did a set on my 69. Engine in stock V8 possition. They really look nice. I got the ones with no brackets or heat tube holes. I also did extensive research to find a set of plug wires that were long enough to wire it correctly from the bottom without having to buy 2 sets or make them. It turned out nice. Ill take a picture to day of the completed engine bay.
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2004 Chevrolet Suburban C1500 2001 Chevrolet 2500HD Crew 6.0 1999 Harley Davidson Electra Glide 1972 Chevrolet C-20 Custom Camper "Dump Truck" 1972 Chevrolet C-20 Suburban "Big Green" 1969 Chevrolet C-50 Wedge Hauler "Leonidis" 1966 C-10 2x4 short fleet 327 4 speed "Race Truck" 1952 Plymouth Cranbrook "Rican" (my grandfathers) 1931 Ford Model A Coupe "Black Beauty" 1930 Ford Model A truck "Club Cab" 4x4 Rottenwood Garage and Speed Shop.....where everything must be racy! It's not just a hobby..It's a LIFESTYLE!!! Thanks for nothing Barrett-Jackson You cant fix stupid or teach accountability! Time wasters, looky Lous and tire kickers are everywhere! Last edited by 72freak; 03-09-2011 at 06:28 AM. |
03-09-2011, 10:24 AM | #5 |
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Join Date: Mar 2003
Location: Cheboygan, MI
Posts: 998
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Re: Headers to 2.5" Ramhorns
Where'd you get those collector tubes? Are they just standard header type?
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Tony Johnson -- '71 Blazer w/L-31 Vortec 350, SM465, NP205, performer intake, edelbrock 1406, HEI, 4" lift, Boyd EFI tank, Vintage A/C My Blazer -- |
03-09-2011, 02:44 PM | #6 | |
Not a bad nut after all..
Join Date: Dec 2000
Location: ND
Posts: 1,756
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Re: Headers to 2.5" Ramhorns
Quote:
Any clearance issues to the starter (and is it the stock full size starter)?
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'05 Chevy 2500HD 4x4 '72 GMC LWB 4x2 driver '72 Chevy LWB 4x4 plow truck '71 Blazer 4x4 driver '70 GMC LWB trailer |
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03-09-2011, 08:42 PM | #7 | |
Rottenwood Garage Member
Join Date: May 2005
Location: Marietta, Georgia
Posts: 4,321
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Re: Headers to 2.5" Ramhorns
Quote:
Normal 2.5 straight runs just like any other dual exhaust with 40 series. No issues. The common myth that there are clearance issues with x-members with the engine in the v-8 position or clearance issues with stock starters is just that...a myth!. I have noticed I will probably need to make a shield for where the exhaust pipe comes close to the front right brake line where it wraps around the frame...its a little close. Yes...collectors welded on to pre bent 2.5 pipe. I told/showed my muffler guy what I wanted and he made them for me. I had 2 sets made exactly the same for the next project.
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2004 Chevrolet Suburban C1500 2001 Chevrolet 2500HD Crew 6.0 1999 Harley Davidson Electra Glide 1972 Chevrolet C-20 Custom Camper "Dump Truck" 1972 Chevrolet C-20 Suburban "Big Green" 1969 Chevrolet C-50 Wedge Hauler "Leonidis" 1966 C-10 2x4 short fleet 327 4 speed "Race Truck" 1952 Plymouth Cranbrook "Rican" (my grandfathers) 1931 Ford Model A Coupe "Black Beauty" 1930 Ford Model A truck "Club Cab" 4x4 Rottenwood Garage and Speed Shop.....where everything must be racy! It's not just a hobby..It's a LIFESTYLE!!! Thanks for nothing Barrett-Jackson You cant fix stupid or teach accountability! Time wasters, looky Lous and tire kickers are everywhere! Last edited by 72freak; 03-09-2011 at 08:43 PM. |
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03-10-2011, 02:06 PM | #8 |
New Member
Join Date: Jun 2007
Location: Coos Bay, OR
Posts: 1,077
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Re: Headers to 2.5" Ramhorns
It was a tight fit to the starter on mine but there is room to make it happen. I ran heat wrap for the first few feet on both sides since it is so close to the starter and transmission cooler lines and the oil filter on the other side.
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03-09-2011, 10:38 AM | #9 | |
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Location: Phoenix, AZ
Posts: 341
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Re: Headers to 2.5" Ramhorns
Quote:
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03-10-2011, 12:36 AM | #11 |
Registered User
Join Date: Aug 2009
Location: Alden NY
Posts: 2,705
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Re: Headers to 2.5" Ramhorns
Nice "unmod". I'm a firm believer in stock exhaust manifolds for a variety of reasons looks, ease of plug access, less heat in the truck, easier on the starter, etc. With the center dump ram horns, the wires were designed to run underneath along the block and up to the plugs with 90 degree angle boots. Cylinders 1,3 and 2,4 actually come up through in-between the block and motor mount. Run like that with the stock heat shields, they shouldn't burn. One other note, if you are keeping your truck stock, I don't believe that the heat stove sheet metal will fit over the 2 1/2 " exhaust manifolds - you would have to stick with the 2".
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1961 C1 Corvette 1959 El Camino 350 TPI, 9" 4 w disc 69 Blazer K5 - sold July '20 2021 Durango RT 5.7 |
11-27-2020, 05:33 AM | #12 | ||
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Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Headers to 2.5" Ramhorns
Quote:
Great tip suggesting 75 Corvette plug wires. Thanks. Quote:
Does anyone have experience using the 76-80 Corvette heat stove with 2.5" ram horn manifolds? https://www.southerncarparts.com/c3-...ield-assy.html They look similar to original stoves but will our stock heat riser and air cleaner work with the Corvette heat stove? Also, can 57-79 Corvette spark plugs shields be used? https://www.southerncarparts.com/195...block-4pc.html
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Photo Gallery of 1972 K/5 Blazer CST Last edited by Green Monster; 11-28-2020 at 04:37 AM. |
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11-27-2020, 06:19 PM | #13 |
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Join Date: Aug 2012
Location: Portland, OR
Posts: 928
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Re: Headers to 2.5" Ramhorns
Green Monster,
I don’t know for sure if it will work/fit but that is exactly what I am (was) planning to do when I get my engine rebuilt. Hopefully someone has done this and can confirm this for us! I am also going to have the ram horns ceramic coated inside and out to reduce engine bay heat. Unrelated, was thinking on having the master cylinder ceramic coated to match so they will look like bare cast iron but not rust. Last edited by PDXk5; 11-27-2020 at 06:43 PM. |
11-28-2020, 04:25 AM | #14 |
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Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Headers to 2.5" Ramhorns
PDXk5- A ceramic coating in a cast iron color on the manifolds and master cylinder will have a nice look for sure.
Yesterday, a pair of Assault Racing 2.5" straight dump ramhorns with black ceramic coating inside and out from Assault Racing showed up at my front door. They were inexpensive ($200) and came with gaskets and all mounting hardware in the photo. Cast iron color was my first choice but black and silver are the only colors offered in ceramic coating, that I could find. The manifolds appear to be two RH (passenger side) manifolds, which is a good thing since there is no ports to drill out, tap and fill as Jim (Jaros44sr) shared he did with his LH manifolds. https://www.assaultracing.com/item/1...?category=8107 The new repo stove and spark plug shields I posted earlier seem like they would fit, function and look close to factory correct. If no one can confirm they won't work then I'll pick up a set and go from there. I need to find out what hardware I'll need for the shields and stoves.
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Photo Gallery of 1972 K/5 Blazer CST Last edited by Green Monster; 11-28-2020 at 04:45 AM. Reason: Corrected grammatical error |
03-10-2011, 11:47 AM | #15 |
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Join Date: Apr 2010
Location: Phoenix, AZ
Posts: 341
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Re: Headers to 2.5" Ramhorns
So reading through this thread, I began wondering if you all would recommend getting the 2.5 ram horns over the factory ram horns? I recently found the factory 2" ram horns that already dump out at an angle in my garage. The PO put headers on my Blazer but I have an exhaust leak so I'm wanting to redo the whole system now. Would the extra .5" be worth while getting the Corvette horns or should I stick with the ones I've got?
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03-10-2011, 12:26 PM | #16 |
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Join Date: Aug 2009
Location: Alden NY
Posts: 2,705
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Re: Headers to 2.5" Ramhorns
They are 25% larger so they will flow better. Probably wouldn't notice on a stock engine. Your Blazer is a 4WD. 4WD used the straight down center dump whereas 2WD uses the angled. I am not sure whether or not you would run into clearance issues with the angled dumps because I have never tried it. Perhaps someone else can tell you.
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1961 C1 Corvette 1959 El Camino 350 TPI, 9" 4 w disc 69 Blazer K5 - sold July '20 2021 Durango RT 5.7 |
06-01-2011, 09:47 PM | #17 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,722
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Re: Headers to 2.5" Ramhorns
It is a 25% larger diameter, but that is not what makes the difference.
If the exit is the largest restriction, the 2" manifolds have a 1 x 1 x pi=3.14 sq inch opening. The 2 1/2" manifolds have a 1.25 x 1.25 x pi=4.9 sq inch opening. That is a 4.9/3.14=1.6 times as much so a 60% increase in area which should have a huge impact on the ability to flow. My opinion is just about any performance level can benefit with the 'vette manifolds. On my truck the "butt-o-meter" said they made more low speed torque than the headers they replaced with no loss on the top end. But it has a little cam, 210 @ .050. This is not a fair apples and apples comparison because the headers had 2 1/4" exhaust with some Turbo King mufflers while the manifolds got 2 1/2" pipe with Dynomax Hemi turbos. Regardless, one of the best mods ever IMO. Good power with low noise and no maintenance.
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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 |
05-31-2011, 09:34 PM | #18 |
Workin to live...
Join Date: Jun 2003
Location: Texas Hill Country
Posts: 261
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Re: Headers to 2.5" Ramhorns
Does anyone know if the Dorman 674-504 lefts will fit Vortec heads? I've got a nice big hole started on the #2 cylinder and I'm tired of the leaking flanges!
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Jason |
06-01-2011, 01:24 PM | #19 | |
Senior Member
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Location: Philadelphia, Pa. 19454
Posts: 9,573
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Re: Headers to 2.5" Ramhorns
Quote:
Thing is, if you run the heat sheilds, you might have a problem with mounting them up. The Vortec heads are about 1/2" taller Main question is...do you run gaskets or not...big debate floating around the boards. I don't, I am just using copper shield. Also, I think the factory locking plates will work best to mount your manifolds, no more loose bolts that create leaks Don't forget you need a new intake, although they make a dual pattern bolt, for the early intakes, the runners are about 3/8" short for the earlier intakes
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Semper Fi...Uncle Sam, you da man All parts offered to help are free, unless otherwise noted Dont try this stuff in my build thread, unless you have 55 years of mechanical OTJ training SAFETY FIRST AS usual, off topic They say your mind goes second, can't remember the first Jim Last edited by jaros44sr; 06-01-2011 at 02:14 PM. |
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06-23-2012, 06:49 PM | #20 |
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Location: Phoenix, AZ
Posts: 341
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Re: Headers to 2.5" Ramhorns
So I am finally getting around to looking into getting these. I don't love the alternator mount but don't really have the means/tools to remove it. Is there a set that will fit without the alternator mount? Like the 674-501? I'm guessing not or there would be more talk about them. Would there be any figment issues if I just left the alternator mount on them?
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06-23-2012, 09:28 PM | #21 | |
Senior Member
Join Date: May 2006
Location: Philadelphia, Pa. 19454
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Re: Headers to 2.5" Ramhorns
Quote:
It was really easy to cut with a angle grinder, and a cutoff wheel
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Semper Fi...Uncle Sam, you da man All parts offered to help are free, unless otherwise noted Dont try this stuff in my build thread, unless you have 55 years of mechanical OTJ training SAFETY FIRST AS usual, off topic They say your mind goes second, can't remember the first Jim |
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06-25-2012, 08:54 PM | #22 | |
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Location: Oakland, Ca
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Re: Headers to 2.5" Ramhorns
Quote:
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06-26-2012, 01:04 PM | #23 | |
Senior Member
Join Date: May 2006
Location: Philadelphia, Pa. 19454
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Re: Headers to 2.5" Ramhorns
Quote:
BTW, nice looking truck!
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Semper Fi...Uncle Sam, you da man All parts offered to help are free, unless otherwise noted Dont try this stuff in my build thread, unless you have 55 years of mechanical OTJ training SAFETY FIRST AS usual, off topic They say your mind goes second, can't remember the first Jim Last edited by jaros44sr; 06-26-2012 at 01:10 PM. |
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06-23-2012, 10:56 PM | #24 |
born to lose
Join Date: Sep 2008
Location: Salt Lake City, Utah
Posts: 842
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Re: Headers to 2.5" Ramhorns
Not to brag but I picked up a used original set locally for 30 bucks! They're going on my truck ASAP since they didn't clear on my Nova. How do you guys like the dormans?
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_____________________ '67 Chevy Belair Wagon 283 Powerglide '68 Chevy II Nova 2 door 350 TH400 Sold!! '71 Chevy C20 350 TH350 '71 Chevy C10 Burb 350 TH350 stolen totalled gone.... Burb Build http://67-72chevytrucks.com/vboard/s...d.php?t=475155 Nova Build http://67-72chevytrucks.com/vboard/s...d.php?t=498979 Wagon Build http://67-72chevytrucks.com/vboard/s...d.php?t=543052 Not giving a truck. |
06-26-2012, 11:24 PM | #25 |
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Location: Phoenix, AZ
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Re: Headers to 2.5" Ramhorns
Thanks Jaros! Time to really start investing in this thing. It's not running properly right now, so I'm working on that now and these manifolds are part of the process. The plan is to use my tax return next year to get some color on it as well. I have some tools but not a ton of power tools. I have a buddy that likely will have one. If it's that easy then time to make a trip to his place!
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