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3/31/12 1:46am - Original Message: 'rams horn manifold questions'
daveo76
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 831
I've all but decided I'm sticking with manifolds instead of going with headers.  Many reasons, but essentially I don't think the incremental power increase outweighs the detriments and the extra cost.  (No offense at all to you guys with headers - they do look cool and do produce more power).  From what I've read in various sources, the original SBC rams horns are actually a pretty good design, but they can be improved on.  My decision now centers around keeping my original 2" manifolds or buying the "Dorman" 2 1/2" aftermarket units.  Any thoughts on whether the 2 1/2" units will really improve flow?  If I buy those I will need to cut off the cast in generator brackets that they all seem to have.   I'm wondering if I'd be better off just doing some cleanup on my originals.  I've read that they can be ported a bit to improve flow.  Any tips for doing that?  I think I'm going to invest in a die grinder.  Should I go with a straight design or 90 degree grinder for this work?  

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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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3/31/12 4:50pm - Reply: 'Re: rams horn manifold questions'
manget1 Lifetime Member
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Indianapolis, IN - USA

Vette(s):
Silver 1974 Convertible - L82 4 speed Low miles (was only 8,900 when I bought it in March 2006) - Now 42K miles. Original owner bought it as an investment for son's college expenses. 2008 Jetstream Blue Convertible - DAILY DRIVER!!

Joined: 9/3/2006
Posts: 2383
Great questions!  I'm eager to hear answers from some of the more knowledgeable people here on the site

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4/1/12 7:08am - Reply: 'Re: rams horn manifold questions'
Stan77
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New Philadelphia, OH - USA

Vette(s):
1977 T-Top Coupe, Black with Buckskin Interior. Restored.

Joined: 1/19/2012
Posts: 8

Through my experiences I have found that, while headers do look cool when you have the hood up at a show, they are not worth the expense if you are building a street cruiser unless you have a "ground pounder" of a motor or plan on doing some racing. They make the car noisey inside and for the street their benefits are negligable. After having headers on some earlier street use performance cars I went back to the tried and true 2" ram horns on my '77. You can have them ceramic coated in a variety of colors, install stn. stl. exhausts and I feel they look just as good as the headers do. As far as performance, while the headers will give you better flow you will never notice the difference on the street. I am sure that some of the other guys will have another opinion but for my money, that is the way I would go.

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4/1/12 2:12pm - Reply: 'Re: rams horn manifold questions'
anips
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 783
if you got a stock motor with 2" exh or 2 into one your wasting your time and money buying new ones using the orginal ones will work, why spend a couple hundred bucks for nothing, if you got a cam, manifold, carb, ign, upgrade,  think about the "street rod shorty headers" if money is an issue they are better than stock at about the same price,  hey guys we drive corvettes, its like  going to the prom wearing sneakers.

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4/1/12 3:47pm - Reply: 'Re: rams horn manifold questions'
daveo76
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 831
My motor is mildly built - medium sized cam, vortec heads, 9.4:1 CR and I have true 2 1/2 dual exhaust (Magnaflow mufflers).  I'm not going with headers, even the shorties, but I will consider the 2 1/2" manifolds - IF they are worth it over the 2" stockers.  I'm not convinced, though.  From what I've read, the originals can be ported a bit to give comparable performance and I talked to a guy that had the aftermarket Dormans at a car show and he was telling me that he's had some cracking problems with them.  (Made in China).   What I'd really like is a set of these babies: 


But they're a bit more than I want to spend right now.  Might be an upgrade I go with in a few years.  (The boss is telling me I've spent too much money on this car in the last year).


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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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4/1/12 9:16pm - Reply: 'Re: rams horn manifold questions'
anips
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 783
As a matter of fact I saw a pair of the speedway RH's on a 32 roadster some  time ago  they look cool, if I remember right they sit just about as high as the valve cover and out a little further than the stock RH's, you might want to consider thinking about clearance problems with them in the vettes engine compartment before you buy, I  don't  believe you you will see any benifit from porting the stock or the 2.5 cast manifolds but at least you have a new tool in your tool box, the way tube headers make additional power is they offer the ability for all the primairy tubes to be in most cases all the same length and flow into the collector in a smooth manner so each one of the cylinders exh event is the same , the Ram Horns by design don't offer that even the Speedway ones, look at the stock manifold, # 1&7 exh. have a longer way to go to the so called collector where #3&5 is short and right out of the exh. port and for all those cylinders not smooth at all, from the intake manifold to the exh. the way to make power is to make it smooth at the right places even if you don't feel it in the seat of your pants its there.

|UPDATED|4/1/2012 7:16:06 PM (AZT)|/UPDATED|


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4/1/12 8:35pm - Reply: 'Re: rams horn manifold questions'
yostusota
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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top

Joined: 5/18/2010
Posts: 1518
Go with the stock ones for now ...if you really want them to look good a good baked on paint will work good for a few years...powder coat...no big deal...I was really responding to the porting issue...really wish you lived nearby!! Here's what I got...it's a half HP Matco straight head rear exhaust one...I have 6 inch long porting bits...prolly got 2 bills in it all...I know you're not doing that but if you do buy one get a rear exhaust one ...big time!! There may be an electric style one out there...once again Harbor Freight may come thru here with something...one other thing I would do is flat file the manifold to head surface...little oil or trans fluid on the file with the manifold in a vice and smooth it out...only takes a few shots and your good.

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My first parade at Carlisle 2010
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4/2/12 12:12pm - Reply: 'Re: rams horn manifold questions'
daveo76
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 831
Thanks guys.  I'm going to stick with the stockers for now and maybe go with the Tru-Ram's in a few years, we'll see.  Anips, I thought about clearance, too, and would definitely check into it before I buy.   And I know that headers make more power from the equal length tuned runners, but my belief is that benefit is really only realized at high RPM's and outside of the normal operating range of a street driven car.   If I ever get into circle track (hey, a guy can dream) I would definitely think about headers.  

Rich, thanks for the porting tips.  I'll look and see what HF has, also Home Depot.  I have a compressor so I'll probably go with an air die grinder, but I'll look for a rear exhaust unit.  One question, what's the reason for the flat filing on the mating surface?  I have a really good straight edge and it shows that the mating surfaces are flat.   I'm going to use gaskets, too, and the stock-style locking mechanisms on the bolts.  


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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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4/2/12 12:37pm - Reply: 'Re: rams horn manifold questions'
yostusota
Former Member
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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top

Joined: 5/18/2010
Posts: 1518
As far as filing the surface..it's just something I do..might knock down some high spots usually around the bolt holes...I'm sure they are not warped..but you'd be surprised at what a flat file will find plus then the surface is perfect for the new set up...I'm not talking about grinding the heck out of it..just put a nice finish to clean any high and low spots.. the port tool has to have rear exhaust!! If not you'll be eating metal filings...yuck..

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My first parade at Carlisle 2010
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4/3/12 10:33am - Reply: 'Re: rams horn manifold questions'
daveo76
Standard Member
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 831
Thanks, Rich.  I'll do some light flat filing on the mating surfaces as you suggest.  I just don't want to screw 'em up!  I haven't decided about painting yet.  I might just wire brush them and then coat with Calyx.  

____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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4/8/12 11:21pm - Reply: 'Re: rams horn manifold questions'
daveo76
Standard Member
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 831
I ended up buying this die grinder (it's rear exhaust, Rich) from Homer Depot:


I'm going to try my hand at porting the collector end of the rams horns.  I also realized I need to do a little bit of work on the intake I'm using.  The gaskets match real well on the heads, but there is a little bit of material that I'm going to remove on the intake side to do some minor gasket matching.  


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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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