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304 vs 360 heads

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Sonic Silver View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2022 at 1:12pm
Originally posted by Trader Trader wrote:

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.
I'm sure that it would be a fun car, similar to the power of an early model 289/4v Mustang, except it would probably drive better. If the car was as light as the Mustang, it should be quicker too.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMCGreen Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2022 at 1:46pm
I have two Edelbrock 4 barrels. bought them in a box of misc parts from a guy. he said both are for a 304. Claimed one had been rebuilt. The other is un assembled but has a rebuild kit. I'm trying to identify them
kit has 50-728-2 on the instruction sheet. all gaskets and pieces still sealed in the original plastic pouches. all unopened.  seems complete.  Just not sure how to ID them
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2022 at 2:36pm
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.
  
I feel like the smaller engines probably weren't as hampered by a single exhaust and 2 barrel carb as the larger ones. AMC rated the 290-2 barrel single exhaust at 200 hp and the 4 barrel, dual exhaust version at 225 with one point higher compression ratio. They rated the 343-2 barrel, single exhaust at 235 hp and the 4 barrel, dual exhaust at 280 with 1.2 points higher comp. I looked up the 360, and the 20 hp increase to 195 net was the dual exhaust on the 2 barrel and the 25 extra to 220 was the addition of the 4 barrel carburetor.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2022 at 2:39pm
Originally posted by AMCGreen AMCGreen wrote:

I have two Edelbrock 4 barrels. bought them in a box of misc parts from a guy. he said both are for a 304. Claimed one had been rebuilt. The other is un assembled but has a rebuild kit. I'm trying to identify them
kit has 50-728-2 on the instruction sheet. all gaskets and pieces still sealed in the original plastic pouches. all unopened.  seems complete.  Just not sure how to ID them
Look up the part number stamped on the front of the carburetor. Then go to Edelbrock or Summit Racing and compare numbers. A 500 cfm should be fine on a near stock 304. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2022 at 2:44pm
If they are Edelbrock's the part number should be here:
If they are Carter AFB's then the number will be on the other side:

That kit number cross references to Edelbrock and Carter AFB 9000 series as far as I can tell.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMCGreen Quote  Post ReplyReply Direct Link To This Post Posted: Jul/05/2022 at 12:39pm
Hope everyone had a good 4th. 
I'm going to try to talk to a shop today. (it's so hot it's a struggle to go out)
And I'm only 10 points away from being able to post a picture.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Jul/05/2022 at 4:09pm
Originally posted by Sonic Silver Sonic Silver wrote:

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.
I'm quoting myself here to make a correction. The 72 model 360 4 barrel intake that I have ends in numbers 989, at least that is what it looks like. The 8 and 9 casting numbers look alike. I do have a #762 also, which is a Machine intake, but I will be using it. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMCGreen Quote  Post ReplyReply Direct Link To This Post Posted: Jul/06/2022 at 1:36pm
I've decided on a shop to rebuild my engine. (looked inside one of the cylinders with a scope and saw ugliness looking back at me)
Hopefully I'll have it in the shop by the end of the month.
the 4 barrel route is sounding like a good way to go. I just need to do more research on what I have vs what's compatible.
I disconnected the exhaust from the manifolds the other day. Of course, one of them hit me on the head. (good thing I don't use it much).

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jul/06/2022 at 1:55pm
Now your talking a different story. The cost to rebuild a 304 is the same as a 360. You may find a 360 that does not need the rebuild cheaper as in many places they are more plentiful. Likely with the 4 barrel already installed.
A crate 304 is the same price as a crate 360 and most of your 304 external pieces, brackets, water pump, steering pump ... are the same.
PO is to do some internet comparison shopping before committing to rebuild the 304 since you were looking for more HP in the first place.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigbad69 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/06/2022 at 4:07pm
Originally posted by Trader Trader wrote:

...and most of your 304 external pieces, brackets, water pump, steering pump ... are the same..
Careful with that one. There a running change with dampers, pulleys and water pumps around that time. The accessories from a later engine may not bolt up.

Always keep the damper and flywheel with the engine to maintain proper balance.
69 Javelin SST BBO 390 T10
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