Rams horn exhaust manifolds

[FLcustom10]

I'm happy I found this thread. I painted mine with POR-15 exhaust manifold paint just to tide me over until I could get headers, but now I'm thinking I'll keep them if the paint holds up.

[CSGAS]

Does anyone know if the ones that come from (shudder) LMC are correct, without any castings to grind off? or are just the drawings in the catalog correct and the parts just Dorman's at a higher price? or something else?

[storm9c1]

The stock Dormans I've seen (the truck versions with the angle dumps) need no casting grinding. They seem to fit fine. They do NOT have any alternator or A/C extensions nor do they have the weird "choke pipe" that the Vette ones have.

The 2.5" center dumps are for the Vette and are different. They can have various different extensions and the chock pipe.

Also, if any ram horns are used on a center-bolt (newer) head, then there is a chance that one side (I think driver's side) has a cast that hits the overhang of the valve cover. In this case, it will need some grinding. At which point, you might as well grind off all of the ugly castings and make them look really smooth while you have the grinder out.

[wilbilt]

Originally Posted by Shaky

An attempt at the best of both worlds would be opening-up your manifolds.

The PO of my recently-acquired C2500 wanted the best of both worlds, I guess.

It has a header on the left side and a rams horn manifold on the right. I am completely serious.

I can't ask him what he was thinking, because he died a few years ago.

[Boog]

He may have been conducting his own tests of which one felt better. The left side or the right.

[wilbilt]

Originally Posted by Boog

He may have been conducting his own tests of which one felt better. The left side or the right.

I guess that's possible, but I have no idea how the resulting documentation would make any sense. It's not like he could switch the parts from one side to the other to compare the results. I guess it will remain a mystery.

For the record, I will be replacing the header with a rams horn to match the other side.

[Shaky]

Originally Posted by wilbilt

The PO of my recently-acquired C2500 wanted the best of both worlds, I guess.

It has a header on the left side and a rams horn manifold on the right. I am completely serious.

I can't ask him what he was thinking, because he died a few years ago.

What does that sound like???

[1967BURB]

So no one ever said will the corvette manifolds work in a 2wd truck?

[Rickey]

Yes I used then on my truck

[storm9c1]

I verified that the stock Vette ones will work, but you will have to fab new pipes. It gets tricky with clearance at the first bend, but it is do-able. You will have to use a mini-starter (Nippon-Denso) style at the very least. You may also have to grind off some casting at the flange, grind the frame, or just loosen the engine cradle brackets and wrestle the engine over about 1/16". Fitment varies by truck.

[FLEET72]

Originally Posted by storm9c1

I verified that the stock Vette ones will work, but you will have to fab new pipes. It gets tricky with clearance at the first bend, but it is do-able. You will have to use a mini-starter (Nippon-Denso) style at the very least. You may also have to grind off some casting at the flange, grind the frame, or just loosen the engine cradle brackets and wrestle the engine over about 1/16". Fitment varies by truck.

I used these.

Granted my engine is mounted in the 6cyl position so no crossmember issues, no grinding of frame or mini starter was required.





I cut about 5 inches off of the upright portion of the pipe and now the horizontal bottom is even or slightly above the bottom of the frame so if in the future I want to slam it, exhaust won't interfere.

[cmg96]

I have a weiand 142 on my mild 350. I was told to get the rams port and polished and use them. I want to build out this motor for quick burst of fun. Like just on cruises hit and woohoo! Would y'all recommend this or another suggestion.

[James the III]

Most do not see any gains with headers because they buy to large of a tube header for the type driving it will see..
The 99.99 specials won't get you any gains..
Like said by many above the rams are fine for most ...
Problem is most get the to big tube.. Or get the smaller tube ones but the collector length is to short..
Smokey Yunick trick of adding length to the collector and keeping all 4 pipes separated in it.. gives huge gains down low and midrange.. but most are not going to rework a header for better power at street driven rpm speeds..

[James the III]

Originally Posted by CSGAS

They do dump straight down but if you put the small block in the "rear position" that clears the crossmember for a straighter shot--the 4X4 ram's horns also come with straight dumps using that position for the engine (dunno the logic) but the Corvette's flow better.

Nice tip on the back motor mount spot to get the straight shot ram horns to clear..
but does this kill the use of an HEI in these trucks putting the SBC in that spot?

[Dad's72]

Since this is an exhaust manifold thread I have a question about my original ram horns from my 72 Super. They are from a stock 350. I am including pictures of something I noticed after I got them off. I guess there was an oil leak and the manifold was cooking it off. Would y'all re-use these? Do they look okay?
Also, I am using a 350 crate motor for 80 to 85. Would these manifolds fit on it?

[storm9c1]

Hit them with a pressure washer, parts cleaner, and/or wire wheel and see if that is coked/burnt oil or the casting itself that is flaking away. Looks like coked oil to me. As long as the casting is still solid, run them.

Of course you will have to replace the flange studs. That alone could go easy... or not.

Wire wheel them down to gray metal. Then a coat of vinegar or other mild acid to etch them, rinse with water, then spray with brake cleaner to remove residue. Let dry for a few mins in the sun. Handle them with clean gloves. Spray with a few coats of Rustoleum BBQ Grill hi-temp flat black paint. Do several very light coats, letting each coat bake in the sun for 10-15 minutes. They will look good.

[Dad's72]

What is the best way to get those studs out? Vice and some vice grips? Spray it down with penetrating oil and let sit. I am wondering if the casting is okay on that burnt looking one. I banged on it with a hammer and it seems solid. The burnt stuff did not chip off from hitting it and not from a wire wheel either. May have to look for a replacement set or just run it till it cracks or leaks.

[mike16]

typically the corvette manifolds are either 2 ' or 2.5 ". the 2.5's came on fullie cars and are rare and expensive.

your carbon build up on your manifolds may come from oil leaking on the manifold or undercoating.

manifolds are good up to a certain rpm level. most trucks dont operate at that rpm level as there is little torque at those elevated rpm levels

trucks came with 2" exhuaste systems so 2.5's wont work unless you are doing a new exhuaste system as well.

if your exuaste system is getting too hot it may be running too rich or not igniting the fuel mixture properly. not the fault of either headers or manifolds.

[custom10nut]

Originally Posted by Indyuke

Yep, bought my truck with headers. They don't leak, they don't get too hot and everything clears just fine. I can even change the spark plugs without taking them off so I just have some nicer ones.

BUT, I don't like them, and I will be putting rams on when the exhaust gets redone.

Same here. Truck had headers when I got it, and at the time I couldn't justify the cost of new Rams Horns. Now, 25 years, 6 fried starters, burnt wires, and three "let me see if these will work" headers, I should have just bought them.
I will get them the next time I replace stuff.

[Sanduners]

Great info. My right side ram horn has a crack, purchased a new set on Ebay. My left side has the 2 bolts holes for the alternator, the new one doesn't. Is there a bracket to use in place of the exhaust manifold bolt holes? Thanks

I didn't even notice those 2 bolts under the alternator supporting it, only once I had all 6 bolts removed and the ram horn wouldn't come out!

[4carbcorvair]

Had Headman Headers on the TBI 350 in my Jeep CJ. Kept leaking at the ball collector. Reason I went with headers is due to the engine mounts, couldn't find cast iron exhaust manifolds to fit until I stumbled apon the 2wd truck ram horn manifolds. Haven't had to touch them since installed. Quieter under the hood, and no leaks.

[BCOWANWHEELS]

blast em inside and out, polish the outside and paint them with bbq grill paint. also test fit the used ones, there known to shrink a little which is no problem a die grinder wont fix, done a many of them. vette 2.5,s will hurt bottom end power unless you have hi compression like the vette did. nothing beats stock ever

[Domingo]

I have a set with the 2 inch out let are they ok on a mild 350

[Mike C]

Originally Posted by BCOWANWHEELS

blast em inside and out, polish the outside and paint them with bbq grill paint. also test fit the used ones, there known to shrink a little which is no problem a die grinder wont fix, done a many of them. vette 2.5,s will hurt bottom end power unless you have hi compression like the vette did. nothing beats stock ever

Starting in '62 is when the 2 1/2" manifolds were first available. And the only motors that came with 2" in the 'vette were the 250 hp and the 300hp with the Powerglide. There was no reduction in low speed torque with the larger outlet manifolds on the low output 300hp motors even. Sometime in the early '70's all of the small block Corvettes received the smaller 2" manifolds and the larger 2 1/2" were discontinuted. Starting in '84 the Corvette received a shorty tubular type header made from stainless.

On my .030 327 (331 ci) that is in my Jimmy I ran Heddman hedders for 10 years or so. At that time the flange where the gaskets met the collector was starting to rust. But I had no real issues with the headers themselves. (3/4" long header bolts using lock washers is the secret here IMO.) I carefully routed and strapped the plug wires (the factory 67-72 trucks wires or the 'vette wires from 75-82 if you have HEI are perfect run from underneath just like with the rams horns)

I noticed no power drop off using my butt-O-meter but the underhood noise was reduced. A good exhaust system with the Corvette manifolds can make as much power as one with a set of headers.... With some caveats. My motor has a 210/210 at .050 camshaft which runs out of steam by 4500 rpm or so. This is the point where above headers MIGHT start making sense. If you are turning a 383 ci engine to 6000 rpm the headers could be worth 50+ horsepower. But unlikely at 4500 rpm.

We are building a Jimmy for my son as well and it is getting a set of 'vette rams horns that have had the brackets cut off and smoothed and then coated with Eastwoods manifold dressing. They look sharp and as I have proven with my truck they work great in that environment. We went with a Summit cam that is equivalent to the Edelbrock Performer 204/214 @ .050 and if I had the Competition Products catalog before I ordered it we may have gone with the Elgin 214/214 cam

The real importance here is for the rest of the exhaust to be excellent as well. 2 1/2" tubing and free-flowing mufflers are a must. On my "old man" truck I went with the Walker Hemi Turbo muffler with the 20" case. On his truck we have some straight through 6" round case Magnaflows that should be pretty lively. We will be piecing together his exhaust using repro Corvette aluminized head pipes and a builder kit from one of the online speed shops.