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1974 AMC 304 options

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pit crew View Drop Down
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Post Options Post Options   Thanks (2) Thanks(2)   Quote pit crew Quote  Post ReplyReply Direct Link To This Post Posted: Aug/29/2015 at 8:14am
I just don't know how much more clearer I can make it that these are estimated numbers. I freaking give up. I am done posting on this forum unless directly addressed.

Quote Don't know your budget but you can also get a compression bump just by switching heads.

If I remember correctly the "517" heads are roughly 52cc as opposed to roughly 58cc for the stock 74 heads. Ballpark numbers translate to a change from 8.4:1 compression to 9.0:1 compression.  That could be as much as a 50hp gain. All rough numbers here and they can vary some.

73 Hornet - 401EFI - THM400 - Twin Grip 20
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nda racer Quote  Post ReplyReply Direct Link To This Post Posted: Aug/29/2015 at 10:14am
The biggest, easiest and cheapest gain is going to a 4bbl. I've posted 1000 times on here it can be worth 9/10 in the 1/4 and that's the only mod. Factory timing. Nothing else changed. I posted the MPH gain somewhere recently and forget it already. I know MPH is you horsepower, but I don't care that much about horsepower, I care about how the whole car works. Aluminum manifold takes weight off the car, esp in the front where it's really important.

I've seen cars run 14sec 1/4s at 120 mph and 13 sec cars run 93. At the end of the day, the 13 sec car wins till you get your combo figured out. Which more often than not is never.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Aug/29/2015 at 6:43pm
There is not an American V8 that will not make more power
when converting from 2bbl to 4bbl.

The 304 is plenty big enough to love a 600+ 4bbl.

Not to mention that you lose about 45 lbs switching from
the stock iron intake to a Eddy dual plane aluminum intake.

if you have one of those nasty iron thermostat outlets
you can save a couple of lbs switching to aluminum.

I did the swap to a Carter AFB on a 1970 Javelin 304
using a 390 iron manifold. The results were stunning!
Gremlin Dreams
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amc401t10 Quote  Post ReplyReply Direct Link To This Post Posted: Aug/31/2015 at 9:38am
After I had my new 74 gremlin(304 auto) about 6 months, I started modding it.
First we're headers,nice seat of the pants improvement, then I put on a alum intake
and a 600 Holley,not much better below 3500rpm, but above that it pulled a little harder,
then I did a cam change(my first) a small crane mabe 280 adv duration, this was the
biggest seat of the pants gain.
After these mods the gremlin was fairly strong, for a high school car.
Raced a 74 vett 350 auto, I pulled him untill about 70-80 mph then he came around.
Raced a 318 auto cuda , pulled it slightly all the way.
Raced a 74 350 auto camaro, stayed side by side to70-80 mph then he pulled me slightly.
Each time the other driver thought they should have smoked me.
Still got 18-20 mpg on trips,14-16 in town.
1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727
84 j10 ,360, 727
1970 4-door rebel sleeper(455 pontiac,turbo 400)
79 spirit,4.2
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Buzzman72 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/02/2015 at 11:17pm
FIRST THINGS FIRST.

Don't worry about putting more fuel and air INTO the engine with a 4-barrel UNTIL you put on some 2" or 2-1/4" dual exhausts to get that spent fuel and air OUT of the engine.

Engine = air pump.

So always, always, ALWAYS do the dual exhaust FIRST.

ALWAYS.
Buzzman72...void where prohibited, your mileage may vary, objects in mirror may be closer than they appear, and alcohol may intensify any side effects.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Rebel Alliance Quote  Post ReplyReply Direct Link To This Post Posted: Sep/03/2015 at 2:15am
Thanks very much for all the replies/help/info.

At this point, the 4bbl, intake, dual exhaust & headers will be the goal for this winter and then go from there time/money permitting.

amc401t10 - I'd love to see a pic of your Rebel sedan. Is it on here somewhere?

I also have a 70 sedan with a 304, but the car is a pretty tired but running/driving project with a good body, so I'm on the fence about my plans with it (time/money/little kids), so some inspiration would be great!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amccar Quote  Post ReplyReply Direct Link To This Post Posted: Sep/03/2015 at 5:07am
Sounds like a good plan. A gear change would be the next change I would make. Mine was ordered from factory with 4.10 gear but speed limit was just 55 back in the 70's.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amc401t10 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/03/2015 at 4:03pm

Here it is mr rebel alliance
pics




1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727
84 j10 ,360, 727
1970 4-door rebel sleeper(455 pontiac,turbo 400)
79 spirit,4.2
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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Rebel Alliance Quote  Post ReplyReply Direct Link To This Post Posted: Sep/04/2015 at 11:09am
Looks like a beast - thanks.

There seems to be very few 1970 Rebel sedans around (or proto-Matadors I suppose) and nearly all that I've seen have a 6 not an 8.

The SST side chrome is bizarre, and I can't think of any other car, AMC or not, that has a half strip like that. Here's mine...

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Snotty Quote  Post ReplyReply Direct Link To This Post Posted: Sep/04/2015 at 2:35pm
That's factory? I was going to ask when the accident happened. Seriously. That's weird.
Son's car: '73 Gremlin X, 401, T-10, Mopar 8.75 rear with 3.23 sure grip. My car: '70 Newport Convertible, 440 automatic
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