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304 vs 360 heads
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Trader View Drop Down
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Points: 6882 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2022 at 8:21am
Agree the intake and carburetor are first. Look for a 3191736, 3195532 or 3199762 and 500 to 600 CFM carburetor - 30 HP.
Next would be free flow manifolds and dual exhaust that will give you 9% more HP (need this anyway if going to a 360 later).
This should bring your 195 net HP up to 245 net HP.
Easiest cost effective 25% gain.
After this, a 360 would be a better starting point as mentioned.
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Originally posted by Trader Trader wrote:

Agree the intake and carburetor are first. Look for a 3191736, 3195532 or 3199762 and 500 to 600 CFM carburetor - 30 HP.
Next would be free flow manifolds and dual exhaust that will give you 9% more HP (need this anyway if going to a 360 later).
This should bring your 195 net HP up to 245 net HP.
Easiest cost effective 25% gain.
After this, a 360 would be a better starting point as mentioned.
I thought that the net hp of a 304 was 150, not 195?
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Correct!
1970-71 304 was listed at 210 gross.
After that, I'm pretty sure it was 150 net.
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Stand corrected, it's 150 net and 210 gross HP by most charts for the 304 2V.
Regardless, the intake, carburetor and dual exhaust are the best bang for the buck bolt on HP gain without tearing down the engine.
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Originally posted by Trader Trader wrote:

Stand corrected, it's 150 net and 210 gross HP by most charts for the 304 2V.
Regardless, the intake, carburetor and dual exhaust are the best bang for the buck bolt on HP gain without tearing down the engine.
According to AMC, the 4 barrel and dual exhaust together added 45 hp to the 2 barrel 360 in 1972. 20 for one and 25 for the other. I can't remember which was which. 360-2 barrel was rated 175 net and either the 4 barrel or dual exhaust made it 195, and the other made it 220.
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Wow! I'm getting such good information from everybody. Everyone has a lot of knowledge and willing to share.  Thank you.
The only thing I know for sure about my car is that it's green. Bright Green.
Anyways, I hope everyone is enjoying their 4th of July.

Ron
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Originally posted by AMCGreen AMCGreen wrote:

Wow! I'm getting such good information from everybody. Everyone has a lot of knowledge and willing to share.  Thank you.
The only thing I know for sure about my car is that it's green. Bright Green.
Anyways, I hope everyone is enjoying their 4th of July.

Ron
I have a 72 model 360-4 barrel intake (the one ending in #736 or 762, I think) if you are interested. I am in upper east Tennessee.
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So basically a 25% HP gain on the 360 which you would also expect on a 304 with the same changes.
360 -    175 x 1.25 = 218.75
304 -    150 x 1.25 = 187.5
Your 304 with a 4V and dual exhaust should be higher HP then a stock 360 with a 2V single exhaust.
Real world experience, a 304 with a 4V dual exhaust was a way nicer motor then a 2V 360 and got better mileage as an added bonus.
  
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Originally posted by Trader Trader wrote:

So basically a 25% HP gain on the 360 which you would also expect on a 304 with the same changes.
360 -    175 x 1.25 = 218.75
304 -    150 x 1.25 = 187.5
Your 304 with a 4V and dual exhaust should be higher HP then a stock 360 with a 2V single exhaust.
Real world experience, a 304 with a 4V dual exhaust was a way nicer motor then a 2V 360 and got better mileage as an added bonus.
  
The only problem is that AMC never made a 304 with anything except a 2 barrel and single exhaust, at least for this country. Not sure about for other countries.
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That's the beauty of the AMC line. You can bolt on any Gen III intake 304-401.
It's not a problem.
Most of the cars had options for dual exhaust 360's also, again, not a problem for exhaust.
If you have ever driven a 304 4V dual exhaust, you would find it being a blast to drive in a smaller car. It's a fast revving little demon of an engine. PO is the net HP of this combination is likely higher. 
A 500 CFM carburetor is acceptable and a 600 CFM can be harder to tune, likely harder with ethanol fuel.
Too bad they don't have more 550 to 580 CFM range carburetors as this would be a nice fit for this build.
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