304 questions

304 questions

Cheepjeep85

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1985 Jeep CJ7, 258, t-176, D300, AMC20, D30
well i'm still exploring v8 motor swaps and i had some questions about the AMC 304 . first off have you ever built one of these motors? what kind of power are you making? how hard was it for you to find performance parts? what kind of special tricks do you have for making good power out of them? i am looking into this because i've found one that i believe i can trade the 350 that needs rebuilding for it, and its complete. although i would rebuild it to, it'll bolt in no adapters required. i'm not looking to make a beast out of it just good power.
 
Most people would tell you to go with a 360 instead of a AMC 304 , it makes more power and all the parts are interchangable, but you have more in the end for the same money. The 360 has bigger heads that flow better then the AMC 304 .

There are lots of aftermarket parts available for AMC 304 up to 401, as the blocks are all of the same dimensions. You can make good power out of a AMC 304 , Bolt on a 4-barrel intake, a good cam and you'll be making good power and better torque, you don't really need headers as the stock manifolds flow pretty good for torque, as you wont be spinnig this thing at 6500.

There is a book out there called BJ builds an AMC, which is highly recommended for rebuilding amc motors, he shows you the "little tricks" you speak of. One of the concerns of a amc motor is the oiling system and his book tells you how to add oil bypass lines and block off this port and enlarge that port, Although he says that oil system modifications aren't neccessary for mild use engines, as oppossed to high RPM race blocks.

I have a 360 in my jeep, I have an edelbrock aluminum intake, 4-barrel, edelbrock cam, and it goes pretty good.

If I was you I'd just add a 4-barrel intake, cam and springs and you should make some decent power and torque. Like I said you will make more power out of a 360 but your trading engines. Your best bet would be to look for a 360 and build it, They are readily available and are almost identical BUT you get the heads with bigger valves.


Blair

Edit>> If your going from the AMC 258 i6 / 4.2l you will need a new frame to motor mount, Im pretty sure it is the passenger side.
 
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I like the 304s quite a lot - my more-serious hotrodding days are past now, I think, and the 304s suit me just fine now. There's no shortage of parts for 'em, and they generate just about as much power as I'm comfortable stuffing into a Jeep that's not to be considered expendable.

You'll want a different Transmission for the AMC 304 - that T-176 is easy to break with a AMC 304 . You'll want a T-18 or a T-98 unless you're OK with a three-speed, in which case a T-15 is a good choice.
 
thanks for the info i can't decide what i want to do yet i was looking at master rebuild kits for the AMC 304 and they run about $600 the same kit for a 350 runs $199 but i'd have to buy adapters for it. so in terms of cost it'll be about the same, the AMC 304 will be easier to swap in so i don't know its up in the air right now
 
I am in the same situation, I have a complete AMC 304 on an engine stand ready to be built up with an Edelbrook Air Gap manifold for it. I paid $275 Canadian for the engine. It comes down to how much horsepower do I need? I am having a hard time finding a 360 where I live and everyone says go with the 360. If I build up the AMC 304 and can get over 200-300hp with a cam, intake, 4bbl and headers that will be good for me. I had a AMC 304 before mildly done up in my 79 CJ7 and enjoyed it, I have never owned a 360. I do miss the rumble and get up and go of the V-8, something my current AMC 258 i6 / 4.2l doesn't have. :)
 
You can definitely get twice the horsepower out of a AMC 304 than you can get out of a stock AMC 258 i6 / 4.2l - no question there. You can get too much, even - enough to really hurt a CJ7 . You can EASILY get plenty 'nuff to hurt a CJ7 out of a 360... which is why I nearly always cringe when I see one in a CJ.
 
A cam and an intake on a AMC 304 will scare most CJ owners, it will rev so fast it will frighten you.


Just sayin' ... :)
 
I know the heads on the AMC 304 don't breath as well as a 360. I heard someone say that you can put bigger Chevy valves in place of the stock AMC 304 valves to make it breath better, I don't know if anybody else has heard this?

If I was to rebuild my AMC 304 , going 30 over, mild cam, Edlebrock intake and 4bbl carb. What could I do to the stock AMC 304 heads to make them work better with my engine mods? Any suggestions? :notworthy:
 
If you start out with real AMC 304 heads - not 292 heads - they breathe just fine. Look as the exhaust ports - if they're lambchop-shaped, you've got real AMC 304 heads. If they're rectangular, they're 292.

Remember... a AMC 304 doesn't have to breathe as MUCH as a 360. It can HAVE smaller valves. Larger valves make for more likelihood of interference with the pistons (NOT something you want!) and a completely different set of unpredictable flow characteristics.

Aaaa, yer just tryin' to come up with a mod you can think about for a while... :)

Na, leave the heads alone. Clean 'em up, paint 'em a real AMC color. Get a valve job done, a three-angle valve job. Test the valve springs, maybe boost the spring tension for that low-duration camshaft.

Does it need boring? Are the cylinders bad enough for that? 30 thou doesn't buy you much HP...

I'm thinkin' a 500CFM carburetor max.
 
~~~ I heard someone say that you can put bigger Chevy valves in place of the stock AMC 304 valves to make it breath better, I don't know if anybody else has heard this? ~~~
This requires notching the cylinder walls.
 
If I was to rebuild my AMC 304 , going 30 over, mild cam, Edlebrock intake and 4bbl carb. What could I do to the stock AMC 304 heads to make them work better with my engine mods? Any suggestions? :notworthy:
same thing i am thinking, i had already figured on 3 angle valve job, and some porting a polishing. anyway a motor for the jeep is going to be put on the back burner, i was talking with my dad the other day and i think we are going to build a stroker motor out of the 350 for his 68 elcamino (i know its an elcamino) but it'll be badass when we done with it and i've been wanting to build a 383 because i've never built one. my jeep already has a new motor, i'll just go with my original plan and do the 4.0 head swap and tbi that should keep me happy. thanks for all of the input, i'll keep my eyes open for a good AMC 304 to build sometime down the road
 
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i was talking with my dad the other day and i think we are going to build a stroker motor out of the 350 for his 68 elcamino (i know its an elcamino) but it'll be badass when we done with it and i've been wanting to build a 383 because i've never built one. my jeep already has a new motor, i'll just go with my original plan and do the 4.0 head swap and tbi that should keep me happy. thanks for all of the input, i'll keep my eyes open for a good AMC 304 to build sometime down the road

sounds nice, I always liked the 68-69's.
You could always stroke the I6 in the jeep too.:D
 

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