Header advice needed!

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Exjouster

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Hey all! Looking to get some oomph out of my 1967 273 in my dart GT vert. Planning on hopefully having it rebuilt to the 1966 275 hp specs or better. (In a perfect world I would love to get 300 hp, but prolly not likely out of my old 273)
Looking to replace the stock exhaust manifolds with headers, and considering these. Any thoughts on these, or what are my other best options?

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Well for HP shorty headers usually are not the best choice, but the lose is not huge over long tube headers and what you gain in clearance to me is worth it usually. I have run Hooker, Dougs, Schmaucher and TTI and a few others mainly on B and E bodies and a few A bodies back in the day. Of course the problems are always space, clearance, sealing and longevity. The better the brand usually the better the fit and sealing. If you spring for good coating, the better the life. I would say this, get the best headers you can afford and I personally recommend getting coated headers. You want thick flanges and something made for your car body style. Just my $.02
 
Those shortys won't fit. AT ALL. The second pair will. They hang a little low. As long as you use at least stock height tires and have the front end at stock ride height they will work ok.
 
Do your best to rudimentarily aim the collectors and tubes. I bought similar shorties for b block dakota and the
collectors aim straight for the pan. Hammered the poo out of em and still we t back to 62-65 b manis. Not even enough room for turn downs. A buddy made an engine stand with a BB 727 case and long tubes hit the tranny pan. I bit the bullet and went with 2” TTI. Couldn’t be happier
 
I'm sure the die hard 273 fans will hammer this . .
step 1) remove 273 place in corner of shop.
step 2) acquire a 318 or 360
step 3) install 1 of the above
step 4) enjoy
 
Hey all! Looking to get some oomph out of my 1967 273 in my dart GT vert. Planning on hopefully having it rebuilt to the 1966 275 hp specs or better. (In a perfect world I would love to get 300 hp, but prolly not likely out of my old 273)
Looking to replace the stock exhaust manifolds with headers, and considering these. Any thoughts on these, or what are my other best options?

View attachment 1715464215

View attachment 1715464216



the shorties i don't see fitting. the long tubes pictures are low hanging garbage. pony up for dougs,tti or just run manifolds.
 
Swap the 273 for a 318 or 5.2 and 300hp will be easy. As stated TTI or Doug's or deal with the low hanging field plow headers.
 
Around the cheap Summit headers on my car for 6 years now and never scrape the ground once.. take those header gaskets they give you with the headers and toss them in the garbage before they cause somebody a nightmare.. spend the $37 and get some remflex gaskets and forget about it...
Take the 273 and hook it to a chain inside your boat and huff it overboard to keep your boat in one place while fishing.. put a 360 in it and tell everybody is a 273... Nobody is going to crawl under your car and try to look at the stamp numbers...
 
Hey all! Looking to get some oomph out of my 1967 273 in my dart GT vert. Planning on hopefully having it rebuilt to the 1966 275 hp specs or better. (In a perfect world I would love to get 300 hp, but prolly not likely out of my old 273)
Looking to replace the stock exhaust manifolds with headers, and considering these. Any thoughts on these, or what are my other best options?

View attachment 1715464215

View attachment 1715464216

Option #2, cam accordingly, the closest cam to the HP 273 would be the MP284/.484, call it a day until you rebuild the 273.

J par says he never had his headers scrape the ground. It must be because his front end ride height is adjusted high &/or taller tires. That will work fine. Not correct if such is the case, but it’ll work. And sometimes, it is what ever works.

Shorty headers are NOT the answer.
 
Do not buy ANY no-name headers off eBay! Only a couple companies make headers that will actually (or almost) fit A-bodies. TTI and Doug's. I can't see any advantage to the shorties except they might be a little easier to install. (and the pictured shorties (OP's) will not fit, that's for certain)
 
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There's nothing wrong with those cheaper long tube headers. Plenty of people have run them for years before Dougs and TTI were even offered. They do hang lower, but as long as your ride height is stock and you run at least a stock height tire, they work fine. I've run several sets. That's about all there "used to be".
 
Like said; slam a bigger engine in there, maybe with Hi-Po log manifolds and never look back.
Look, I'm not slamming 273s or 318s; I've owned and driven them both.
Your vert is pushing 3200pounds loaded, so when you say 275/300 hp, what you are really saying is 3200/300=10.67 pounds per horsepower.
But what you mean is X pounds per cubic inch, at a certain specific power output.
So for 300hp on a 273 you are saying 1.1 hp per cube which is getting to be a pretty specific build.Whereas
a 318 would need only .94 hp per cube, and
a 360 only.83 hp per cube
All of these engines weigh about the same.
All of these will cost about the same in basic machining.
The 360 will be happy with large-port heads and support works. Heck,it already comes with the right heads.
Pistons for the 360 are cheap. It will cost you close to double for 273 pistons.
Heck the 360 will make 300hp with just a cam and bolt-ons; super cheap
But here's the thing;
300 hp from a 273 is not the same as 300hp from a 360.
Each of these can be built to make the same number for a little better than an instant at some point in the rpm band. So if you got a boat, fine prop it right, and go; 300 is 300.
But your vert is not a boat, and the engines have to operate at every rpm between stall and whatever rpm 300hp comes at,and beyond; and the bigger engine will make more power than the smaller both coming and going. So the bigger will make more average power over any given rpm range.
So the question is; why spend more money for the 273 to get less actual performance?
There are only two justifications;
1) you don't care about the cost, or
2) you just want the 273
I mean no one can argue against these.
 
Hater....
:rofl:
Like said; slam a bigger engine in there, maybe with Hi-Po log manifolds and never look back.
Look, I'm not slamming 273s or 318s; I've owned and driven them both.
Your vert is pushing 3200pounds loaded, so when you say 275/300 hp, what you are really saying is 3200/300=10.67 pounds per horsepower.
But what you mean is X pounds per cubic inch, at a certain specific power output.
So for 300hp on a 273 you are saying 1.1 hp per cube which is getting to be a pretty specific build.Whereas
a 318 would need only .94 hp per cube, and
a 360 only.83 hp per cube
All of these engines weigh about the same.
All of these will cost about the same in basic machining.
The 360 will be happy with large-port heads and support works. Heck,it already comes with the right heads.
Pistons for the 360 are cheap. It will cost you close to double for 273 pistons.
Heck the 360 will make 300hp with just a cam and bolt-ons; super cheap
But here's the thing;
300 hp from a 273 is not the same as 300hp from a 360.
Each of these can be built to make the same number for a little better than an instant at some point in the rpm band. So if you got a boat, fine prop it right, and go; 300 is 300.
But your vert is not a boat, and the engines have to operate at every rpm between stall and whatever rpm 300hp comes at,and beyond; and the bigger engine will make more power than the smaller both coming and going. So the bigger will make more average power over any given rpm range.
So the question is; why spend more money for the 273 to get less actual performance?
There are only two justifications;
1) you don't care about the cost, or
2) you just want the 273
I mean no one can argue against these.
 
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