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Best Header Manufacturer
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clanofwolves View Drop Down
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    Posted: May/20/2015 at 7:24am
I am looking at replacing the factory exhaust manifolds on my 304 (Sept 28, 1970 manufacture date) and I was wondering what the best headers are. I have read some comments on many posts of some headers that have issues with standard starters and even some that need modification to install them at all. I'm not sure this is a good option unless there is a company that makes headers that are "plug-and-play" so to speak.

Thanks for any assistance!!

Dave 
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Points: 6236 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 6768rogues Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2015 at 7:56am
I have headers on my 68 Rogue 360 and I will never use headers again. It is a real pain to install the right side and takes about 2 hours. To replace a starter, the header and starter have to come off together, after disconnecting the tranny mount, one engine mount, shoving the tranny over to the left and taking off some of the suspension. The collectors hit some speed bumps and the gaskets are prone to leaks. I made a heat shield to keep the header from cooking the starter.
Unless you have a high horsepower race car, which your 304 probably is not, I would use manifolds and have fewer issues.
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Clanofwolves . I have yet to see a set of plug and play headers for any AMC . get a set of free flows and your done .
thats plug and play .
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Hooker, and Doug's, but you are dealing with a 304.

The biggest bang for the buck is dual exhaust and a good intake and carb.

Even with stock valve springs and cam, I had good power with a 650 vac secondary, on a high rise manifold. Because I knew the 304 did not have the cam and volume for such a combo, I moved the carb 1 inch higher from the plenum, using a carb spacer. It was pushing the extremes of cable adjustment, but fit nicely. Since I had an amx hood i had clearance for the air cleaner.

The next thing I did was to tweak the distributor with a kit. Did not take too much to do and will do more for you than bolting on headers. 

I recommend headers as something you do once you make further mods completed with the 304.

Remember... Power is volume and burn efficiency. The header will allow for better scavenging but if exhaust is restrictive by too much back pressure the header is fighting a lost cause. Plus if you have less flow capabilities at the intake and carburetor the header will not be able to perform as well.
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pit crew View Drop Down
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Points: 5341 		Post Options Post Options   Thanks (0) Thanks(0)   Quote pit crew Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2015 at 8:11am
Been there, done that. Had headers on my 304 Hornet. The downsides are they dump heat in the engine bay, add to passenger cabin noise, limit ground clearance, and can be a bugger to get to seal. I have fuel injection with an O2 sensor so a good exhaust seal is critical.

Unless you are going for that race car look or are building a race car I would suggest factory manifolds. I went with the dog leg free-flows with 2.5 dual exhaust pipes and have been very happy ever since. I used that KBS bush on coating and they look great. You can almost see them in the picture. Sorry, best picture I could come up with on short notice.






Edited by pit crew - May/20/2015 at 8:14am

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I have to disagree!
Yes they are a bitc=+^ to install.
Yes u have to retighten about 10 times.
Use a mini starter will help!
I have Headman headers on 3 of my cars with no problems.
I have tried others,don't like them.
Must use headman header gaskets .
If u have dog leg heads, and don't use headers, u r missing a chunk of HP and TQ.
I soak the gaskets in warm water for at least a hour. Install , let run until hot,
Let cool to touch, retighten, run until hot, retighten, at least 4 times before a drive.
Then retighten once every 50-100 miles, 3-4 more times.
This has worked for me.
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73hornut View Drop Down
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Points: 3130 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 73hornut Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2015 at 9:25am
The only "plug & play" headers, are the pertronix(edelbrock). At this point, too expensive, for the nominal gain.
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Originally posted by pit crew pit crew wrote:

Been there, done that. Had headers on my 304 Hornet. The downsides are they dump heat in the engine bay, add to passenger cabin noise, limit ground clearance, and can be a bugger to get to seal. Unless you are going for that race car look or are building a race car I would suggest factory manifolds. I went with the dog leg free-flows with 2.5 dual exhaust pipes and have been very happy ever since. I used that KBS bush on coating and they look great.
Good experience and advice pit crew; beautiful engine BTW; wow!!

Originally posted by toolmanxiii toolmanxiii wrote:

Clanofwolves . I have yet to see a set of plug and play headers for any AMC . get a set of free flows and your done.

Thanks toolmanxiii, I love experience dovetailed with clear advice!

Originally posted by 6768rogues 6768rogues wrote:

I have headers on my 68 Rogue 360 and I will never use headers again.

 

Great experience, I really like the history too; helps an AMC novice such as myself in a huge way! Thanks! You guys rock!!

Dave
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Points: 5341 		Post Options Post Options   Thanks (0) Thanks(0)   Quote pit crew Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2015 at 9:53am
Originally posted by clanofwolves clanofwolves wrote:

Good experience and advice pit crew; beautiful engine BTW; wow!!
Thank you. It has been fun building it up over the years and trying different configurations. Good luck with your decision.

Best advise I could give is to keep your end goal in mind as you move forward. Headers for a race car are a no brainer but I would think it over before I would put them on a street car.

I'll happily wrench day in and day out on a race car but for me a street/cruise car should be comfortable to drive and fairly low maintenance but then again I am getting older now. Wink

Ken

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Points: 1814 		Post Options Post Options   Thanks (1) Thanks(1)   Quote Ken_Parkman Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2015 at 10:10am
A different point of view from a performance guy. On the dyno on a 425 ish hp 401 back to back a set of 1 3/4" headers was worth 20 hp and 30 ft-lb of torque through the mid-range. That is performance you can notice and feel. Even on a 304 good headers and duals are significant, and a shorty or manifold cannot build the mid range torque a proper header can.

There are downsides, and the biggest problem is ground clearance. The 7105 hooker is a little better than the 98310 headman (small body car), but it's still easy to whack the pipes, especially passenger side. Don't lower the car, and you learn to hate speed bumps.

Don't use the cheap white gaskets, get a good set. Also copper silicone will properly seal and prevent leaks. Never a leak in the last 25 years after I figured out gaskets.

Starter installation is a big pain on a small body car. If everything is stock you can relatively easily install a stock starter with a 7105 Hooker cause it has a removable # 8 primary. BTW the primary must be clamped at the bottom. The Headman is a huge pain but it can be done if you know the trick. Mini-starters do make it a lot easier, and are almost a requirement once you start getting into better oil pans.

Port port fit can also be a problem. The 98310 Hedman is really quite bad as the 1 5/8" does not fit the dogleg well at all. The 7105 Hooker is usually decent, but sometimes terrible. Don't understand.

To me the problems are worth it for sure. 20 real hp and 30 ft-lbs through the mid range is big. Depends on your goals for the car.
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