Dyno Test Comparison between Rams Horns and Headers...
Le Mans Master
Joined: May 2008
Posts: 9,063
Likes: 2,736
2022 C3 of the Year Finalist - Modified
Ahhh....just ignore me. Sorry, for posting. I just get in moods about some of this stuff, and try to make points, but its normally not what people want to hear. We all do what we want, and we justify it so we feel good. Nevermind.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
To answer your question from your previous post, there was a notable difference going from my rams horns to the 1 5/8” headers back in 03/04. This was a street driven car then and I don’t think I’d seen even an autocross yet.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I disagree. 20 peak horsepower more on a set of undersized headers vs a set of custom-ported manifolds, plus the average power differences across the entire curve. If the engine were equipped with 1 3/4" or 1 7/8" headers, we may have seen a power gap of 30 or 40 peak hp. At this point, with this motor, would you chase a little more cam to get a little bit more power and shift the RPM range up, or go with long-tube headers and make more power everywhere in the curve? Not to mention, if you had started with stock ram's horns, the work to replicate this may be equivalent to, if not more expensive than just buying a set of headers. I'd also be very curious how the stock ram's horn setup compares to the ported setup. (@StraubTech - that port work is beautiful, by the way.)
I think the takeaway here is if your build is constrained to manifolds, you can do work to them to minimize the amount of power you're losing not going to a full length header. Straub's point is excellent - there's plenty of race classes that require manifolds. If your car doesn't have header fitment, you don't like them for packaging reasons (spark plug access, ground clearance, heat management) or you can't do it for smog reasons, this shows that ported manifolds are a very viable alternative.
But I wouldn't herald this data point as "the guys who have been championing long-tube headers are wrong", which a lot of people in this thread seem to be doing.
This may be the last time I join in on one of these threads, but I will continue to cite that my personal experience has proven without a doubt (to me, anyway), that even a puny little L-48 can get a nice performance wakeup going from stock manifolds to headers.
I think the takeaway here is if your build is constrained to manifolds, you can do work to them to minimize the amount of power you're losing not going to a full length header. Straub's point is excellent - there's plenty of race classes that require manifolds. If your car doesn't have header fitment, you don't like them for packaging reasons (spark plug access, ground clearance, heat management) or you can't do it for smog reasons, this shows that ported manifolds are a very viable alternative.
But I wouldn't herald this data point as "the guys who have been championing long-tube headers are wrong", which a lot of people in this thread seem to be doing.
This may be the last time I join in on one of these threads, but I will continue to cite that my personal experience has proven without a doubt (to me, anyway), that even a puny little L-48 can get a nice performance wakeup going from stock manifolds to headers.
Scotty
Race Director
Joined: Mar 2016
Posts: 14,402
Likes: 8,209
From: Napa Valley California
Back when I was in high school, I purchased a 70 SS Chevelle with the 396/402 big block.
Since I was only working part time after school I had very little money for extra speed equipment for my car.
The first thing I did was install a set of Hooker tuned headers and turbo mufflers.
Adding the headers alone made a noticeable difference in the performance during around town driving.
It didn’t make it a monster in any way, but it did run smoother and the headers added some noticeable improvement in the acceleration.
In 72 I replaced the Chevelle with a Buick Skylark, GS with a 455.
I also added Hookers to that car and again experienced the same results as I did with the Chevelle.
Seat of the pants dyno results will show some improvement between 1500 and 2000 rpm.
Above 2000 rpm’s and the performance improvement will be more significant.
Team Owner
Joined: Jun 2001
Posts: 43,136
Likes: 155
From: Thomson Georgia
In my personal experience, the answer to your question is yes.
Back when I was in high school, I purchased a 70 SS Chevelle with the 396/402 big block.
Since I was only working part time after school I had very little money for extra speed equipment for my car.
The first thing I did was install a set of Hooker tuned headers and turbo mufflers.
Adding the headers alone made a noticeable difference in the performance during around town driving.
It didn’t make it a monster in any way, but it did run smoother and the headers added some noticeable improvement in the acceleration.
In 72 I replaced the Chevelle with a Buick Skylark, GS with a 455.
I also added Hookers to that car and again experienced the same results as I did with the Chevelle.
Seat of the pants dyno results will show some improvement between 1500 and 2000 rpm.
Above 2000 rpm’s and the performance improvement will be more significant.
Back when I was in high school, I purchased a 70 SS Chevelle with the 396/402 big block.
Since I was only working part time after school I had very little money for extra speed equipment for my car.
The first thing I did was install a set of Hooker tuned headers and turbo mufflers.
Adding the headers alone made a noticeable difference in the performance during around town driving.
It didn’t make it a monster in any way, but it did run smoother and the headers added some noticeable improvement in the acceleration.
In 72 I replaced the Chevelle with a Buick Skylark, GS with a 455.
I also added Hookers to that car and again experienced the same results as I did with the Chevelle.
Seat of the pants dyno results will show some improvement between 1500 and 2000 rpm.
Above 2000 rpm’s and the performance improvement will be more significant.
I wish I had that Skylark w/455. Talk about Monster Tourque. What was the H.P.? Gear ratio? Manual?
Race Director
Joined: Mar 2016
Posts: 14,402
Likes: 8,209
From: Napa Valley California
I couldn’t tell you what the torque and hp were.
At the time it was the hot set up off the assembly line.
It was the 455 with the TH400 and what the rear gear ratio was I don’t recall.
I pulled the heads and had them worked by a local machine/speed shop, installed a hi lift cam, replaced the intake and installed a set of dual Holley’s, Hooker headers, turbo mufflers and an Accel dual point distributor.
The suspension and wheels were all stock and it was the perfect sleeper.
At the time it was the hot set up off the assembly line.
It was the 455 with the TH400 and what the rear gear ratio was I don’t recall.
I pulled the heads and had them worked by a local machine/speed shop, installed a hi lift cam, replaced the intake and installed a set of dual Holley’s, Hooker headers, turbo mufflers and an Accel dual point distributor.
The suspension and wheels were all stock and it was the perfect sleeper.
Burning Brakes
Joined: Oct 2020
Posts: 1,149
Likes: 265
From: The frozen wastes...
In my personal experience, the answer to your question is yes.
Back when I was in high school, I purchased a 70 SS Chevelle with the 396/402 big block.
Since I was only working part time after school I had very little money for extra speed equipment for my car.
The first thing I did was install a set of Hooker tuned headers and turbo mufflers.
Adding the headers alone made a noticeable difference in the performance during around town driving.
It didn’t make it a monster in any way, but it did run smoother and the headers added some noticeable improvement in the acceleration.
In 72 I replaced the Chevelle with a Buick Skylark, GS with a 455.
I also added Hookers to that car and again experienced the same results as I did with the Chevelle.
Seat of the pants dyno results will show some improvement between 1500 and 2000 rpm.
Above 2000 rpm’s and the performance improvement will be more significant.
Back when I was in high school, I purchased a 70 SS Chevelle with the 396/402 big block.
Since I was only working part time after school I had very little money for extra speed equipment for my car.
The first thing I did was install a set of Hooker tuned headers and turbo mufflers.
Adding the headers alone made a noticeable difference in the performance during around town driving.
It didn’t make it a monster in any way, but it did run smoother and the headers added some noticeable improvement in the acceleration.
In 72 I replaced the Chevelle with a Buick Skylark, GS with a 455.
I also added Hookers to that car and again experienced the same results as I did with the Chevelle.
Seat of the pants dyno results will show some improvement between 1500 and 2000 rpm.
Above 2000 rpm’s and the performance improvement will be more significant.
You didn't even get the half ov it. I can guarantee you those 'turbo' mufflers cost you a LOT ov HP. Hell, they might have almost negated what the headers gave you. Not that it was an option back then, but had you had a GOOD mandrel system, at least 2.5", and some Magnaflow 'dyno specials' you'd have gained a fair bit more. Those turbo mufflers were awful. Like, worse than glasspacks... (and thats pretty damn bad).
My grade 12 daily was a basher 70 Skylark with a legit 70 455 Stage 1 swapped in. The rest ov the car was utter ****, but it was so rusty, and gutted that it only weighed about 3350lbs. If i'd have known then what i know now about speed... Jesus. Mine had those horrific 'turbo' mufflers too... running into sidepipes. I probably lost 50HP through that mess. That... was a scary car...
Burning Brakes
Joined: Oct 2020
Posts: 1,149
Likes: 265
From: The frozen wastes...
I agree. The ported manifolds did a commendable job. I would not use this as a basis for argument in a "should I do stock manifolds or headers", though - we are not comparing apples and apples here. And a key point is that the undersized headers still did better throughout the powerband.
And thank you, Straub, for the info.
I will try to get a picture of a stock Ram's Horn port later.
And thank you, Straub, for the info.
I will try to get a picture of a stock Ram's Horn port later.
To be fair, if those manifolds came off that race engine, it might have been designed around them... in which case it would not suffer for them as much as a normal HP engine would. Just ask the F.A.S.T. guys... all manifolds, but they design very custom cams around those severely ported manifolds... just like the Super Stock guys used to do. If you build an engine around a manifold rule, you can work some serious magic to negate the losses. Very different than just bolting the ported units onto a hot LT1.
Further... those manifolds are clearly someone's baby. Nothing even close to stock. There was a F.A.S.T. guy in one ov my many car mags years ago who was hedging around the questions as usual. I THINK (???) it was a big block Nova guy? This was before most ov the 'tricks' got out... About his manifolds he said only 'You dont wanna know how much time has gone into these. If i had to pay someone to do this, it'd be cheaper to buy custom stainless headers (read: 3-5K)...'
The moral ov this story... unless you are racing a class, trying to remain stock looking, or (i get it, i honestly do...) just loathe dealing with headers... Yeah, just use longtube headers and be done with it.
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