Shorty Headers

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My opinion. If the stock manifolds are a limiting factor in just flow (273 early A is likely a good example) then yes the shorties will help. Shorties (and stock manifolds) are too short to do what header’s actually are suppose to do, scavenging to actually boost power. You need about 28”-36” tubes to do that. Tube size is another hot topic. There is some simple math to size the tubes. If they are shorties and not helping with scavenging go as big as you want. If long tube too large it can cause a decrease in the wave velocity so it does have enough energy to do a good job of starting the backwards wave up the other cylinders tube to effectively scavenge the cylinder. Again simple math with the cylinder volume will size the tube.
 
Jim Kueneman said:
My opinion. If the stock manifolds are a limiting factor in just flow (273 early A is likely a good example) then yes the shorties will help. Shorties (and stock manifolds) are too short to do what header’s actually are suppose to do, scavenging to actually boost power. You need about 28”-36” tubes to do that. Tube size is another hot topic. There is some simple math to size the tubes. If they are shorties and not helping with scavenging go as big as you want. If long tube too large it can cause a decrease in the wave velocity so it does have enough energy to do a good job of starting the backwards wave up the other cylinders tube to effectively scavenge the cylinder. Again simple math with the cylinder volume will size the tube.
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Go to bed, Jim! LOL
 
One year, later ……

What do you guys think about this combo? I have a 73 440-4spd Duster. I have TTI step headers on the shelf and 1.03” t-bars.
MY concern is fit and not power. I have an LD340/224* @.050” HFT, z and O heads. In the future I may be making more hp and cam with a change to ported iron heads and Air Gap. I don’t care to make over that.

The goal is handling so I will be going with large diameter t-bars, which is my concern. Turns out you don’t need 500 hp to be any more competitive on an auto-cross course. Where the power is will be more important.

I want: access in the engine bay, clearance of the torsion bars.

A big question I have is are the step headers going to be worth shoehorning in to place and dealing with clearancing tubes and modifications to the z-bar?

In light of my power goals are long tubes really necessary? And for that matter, are short headers going to be better in any way that manifolds.

Realistically, 350-375 hp will probably be the most horsepower my engine may get to.
 
i say if you can get the step headers to fit to your liking use them. picking up some precious torque in the midrange and getting some horsepower when you're legging it out instead of shifting on the course might be worth fractions of a second.

i wouldn't say that headers would be "necessary" for your application and intended power goals, but i would certainly recommend it, or 340 manifolds if you've got those on the shelf.

will shorties be better than manifolds, sure but not by a wide margin. it's up to you to decide if that margin is worth 7~800 bucks.
 
junkyardhero said:
i say if you can get the step headers to fit to your liking use them. picking up some precious torque in the midrange and getting some horsepower when you're legging it out instead of shifting on the course might be worth fractions of a second.

i wouldn't say that headers would be "necessary" for your application and intended power goals, but i would certainly recommend it, or 340 manifolds if you've got those on the shelf.

will shorties be better than manifolds, sure but not by a wide margin. it's up to you to decide if that margin is worth 7~800 bucks.
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Thanks, The money isn't a big issue as I have the NIB TTi step headers and could sell those and buy shorties for a break-even deal. BUT, shorties sound like they are good for ONE thing and it aint power gains. They simply appeal to me because, weight and it more clearance.
Are Shorty headpipes going to be the same sink drain looking mess as my manifolds or do they improve over stock in that area? Once upon I time I had the engine/trans/k-member/torsion bars mocked up on a k-frame dolly. The bars were 1.24" and I mocked up my 1-5/8 steps and major tube manipulation appeared to be in order. Granted those are the biggest bars they make and I will now be getting 1.18" bars. My original intent was to use this combo on a 550 hp engine. The headers were going to be at the top of their limit for gains. That car was ruined so I am putting my efforts into a lower powered car where the step headers may be too much. Thoughts?
 
Hey Go-Fish,

Im in agreement with the guys on here who say long tube are better for power/torque gains. Also, I think with shorties there is a gain over just HP manifolds.

My main concern was serviceability and ground clearance using a 4-speed.

I spoke to the people at TTi . They are the experts and do this stuff all day. I got pretty much the same response as posted by Rusty Rat Rod and Rat Bastid.

They also recommended the setup I have on my car now with 2 1/2 pipes, x -pipe and ceramic coated shorties.

Gives me exactly what I wanted and I don't think you will tuck the exhaust system up much tighter than this in an A-Body.


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Super-Cuda said:
My main concern was serviceability and ground clearance using a 4-speed.
Click to expand...

Yep, same here. There are other performance improvements I can do to help myself more (for MY application) like large torsion bars, sure-grip, gearing, tire size, stiffening.

My header concerns aren’t necessarily getting the most power potential because that would require deviating from my engine approach. I WANT to keep iron heads and don’t want to make the engine make much more power, necessarily.
I don’t want hinderance to accessibility, clearance headaches, and “too much” header for iron head CFM outputs.
 
If engine access is you're concern, what's to access down the side of the block below the ports, with shorties winding back and forth you can't even see the side of the block.
People act like you take headers off every week.
I raced for years, took heads off over the fender, loose headers, long or short once undone move back and forth a few inches to access the head bolts, other than that, what access do you think you need.
Fitment to torsion bar is usually at the collector, if it's close and needs a tweek, I use a ratchet strap around the trans or T-bar, being carefull not to trap cooler lines etc, then cinch it up till the header bends enuff for the minor clearance. More clearance needed, I have stuck a fence-post up the collector, then a nudge one way or other, (don't knock the vehicle off the lift). I have also put a ratchet strap around that fence-post and the leaf spring, and sucked it over. Another instance on a bb Chally, I put the header in a vice and "draw filed" the head flange to make the header leave the head at a different angle for clearance on something. (That header was fucked from factory)
You don't have to Change the angle at the head much, go get a 3/16 clearance down by steering .
I haven't had to ding a header in years since I realized I can bend the header as a whole to eliminate a rattle, or create clearance without a hammer, thus not fracturing the ceramic coatings inside or out.
Hope it helps, cheers

(This is after you have moved the engine as much as possible after loosening/tightening fasteners etc .)
 
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inertia said:
If engine access is you're concern, what's to access down the side of the block below the ports, with shorties winding back and forth you can't even see the side of the block.
People act like you take headers off every week.
I raced for years, took heads off over the fender, loose headers, long or short once undone move back and forth a few inches to access the head bolts, other than that, what access do you think you need.
Fitment to torsion bar is usually at the collector, if it's close and needs a tweek, I use a ratchet strap around the trans or T-bar, being carefull not to trap cooler lines etc, then cinch it up till the header bends enuff for the minor clearance. More clearance needed, I have stuck a fence-post up the collector, then a nudge one way or other, (don't knock the vehicle off the lift). I have also put a ratchet strap around that fence-post and the leaf spring, and sucked it over. Another instance on a bb Chally, I put the header in a vice and "draw filed" the head flange to make the header leave the head at a different angle for clearance on something. (That header was fucked from factory)
You don't have to Change the angle at the head much, go get a 3/16 clearance down by steering .
I haven't had to ding a header in years since I realized I can bend the header as a whole to eliminate a rattle, or create clearance without a hammer, thus not fracturing the ceramic coatings inside or out.
Hope it helps, cheers
Click to expand...
Thanks. When I had everything mocked up there was significant interference with big bars. Not that it couldn’t be massaged but with my meager power requirements (mid to high 300’s) how are long tube headers going to perform? How will it benefit me to have 500 horsepower headers on a 350 hp engine? Can you have too much header? Real question.
 
I have had the pleasure of installing lotsa headers, I can tell you the ****-faced grin on every face that came back after a test drive, never complained once .
Then they open the headers, and the grin gets huge .
 
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