Re: which heads for my 400 engine?
[Re: paddel]
#1821805
05/08/15 01:24 PM
05/08/15 01:24 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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About to go away
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With a stock piston 400 it really doesn't matter what heads you run, compression is going to be low with no quench.
You'd be better off getting new pistons to fix the low compression rather than new heads at this point.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: which heads for my 400 engine?
[Re: paddel]
#1822090
05/08/15 08:11 PM
05/08/15 08:11 PM
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Joined: Jun 2010
Posts: 23 Tucson,AZ
Remow2112
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I run the 84 cc Edelbrock heads. I have headers, rpm intake on a low compression motor. Gets my 3500 pound Volare to 12.4 in the 1/4.
If I were buying again I would get the sidewinder heads.
Also, I run a steel head gasket.
Last edited by Remow2112; 05/08/15 08:11 PM.
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Re: which heads for my 400 engine?
[Re: paddel]
#1822500
05/09/15 10:06 AM
05/09/15 10:06 AM
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Joined: Feb 2005
Posts: 4,316 Prospect, PA
BSB67
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Prospect, PA
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I think you are on the right path. Not only would I purchase the 75 cc head, I would mill it to the desired compression ratio, or to the highest compression ratio with a reasonable cut on the head.
Giving up 10 cc on a low compression motor when you are already buying heads and doing the work just does not make sense.
Most people misunderstand what increasing CR does. There are formulas out there that that people use that generally show you the increase in peak power. These power increase numbers are modest and understate the actual result. Increased CR is one of the simple few things that you can do to increase the power from idle to red line. If you take an engine's power curve, and change nothing but engine's compression ratio, the entire power curve moves up. For the same change in peak horsepower, the CR change will result in more average hp increase.
Last edited by BSB67; 05/09/15 10:40 AM.
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Re: which heads for my 400 engine?
[Re: BSB67]
#1822507
05/09/15 10:30 AM
05/09/15 10:30 AM
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Joined: Feb 2005
Posts: 4,316 Prospect, PA
BSB67
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Prospect, PA
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Wow, what a coincidence. Look at this curve. If you follow how power curves change with typical performance upgrades, you will know that there usually isn't one change that can result in this kind of change in the area under the power curve. https://board.moparts.org/ubbthreads/ubbt...tml#Post1821935
Last edited by BSB67; 05/09/15 10:36 AM.
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Re: which heads for my 400 engine?
[Re: ahy]
#1822609
05/09/15 01:01 PM
05/09/15 01:01 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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About to go away
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Any of the heads you are looking at will give you more flow, more power and less weight. I don't think compression differences will have a big effect with the current build. It will with any kind of a cam. low compression engine + high performance cam = crappy combo.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: which heads for my 400 engine?
[Re: paddel]
#1822675
05/09/15 02:35 PM
05/09/15 02:35 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
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Lincoln Nebraska
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is this a stock 400 with open chambered heads? How soon/serious are you about replacing it with the stroker? As said SCR is where you are hurting. you could mill the heck out of the open chambered heads or get a set of 516 iron closed chambered heads & home port em (tho you are in Germany/not sure what's available there) & as you know it would not be practical to ship some OE lo po iron heads. You could go with the alum heads with the smallest chambers & adv the oe stock (I'm assuming) cam 4 deg & dial in the dist subsystems then transplant the alum heads when the stroker comes together.
live every 24 hour block of time like it's your last day on earth
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Re: which heads for my 400 engine?
[Re: paddel]
#1823586
05/10/15 07:04 PM
05/10/15 07:04 PM
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Joined: Feb 2003
Posts: 21,318 Manitoba, Canada
DaytonaTurbo
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Manitoba, Canada
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I know I won't see anything above 9,5:1.
With a 74 400 on stock pistons you won't see anything NEAR 9.5 with a head change. Even with a set of 440 source heads milled down to 75cc you still won't see above 8.5 compression, likely closer to 8.0. Which is still better than your stock 7.5 of compression. You can get a smogger 440 to perform decent, but your gains will be in: Distributor tuning carb tuning exhaust cam torq converter rear gear. The cam you are choosing is very mild, a good choice for your compression and gear ratio. Your car will be a good cruiser but not a ground pounding, tire shredding machine. IMO if your stock heads are in ok shape, run them. Now if you were building for 1/4 mile performance, not highway cruising, I would go to a 4.10 gear, 3000rpm stall converter, move up a few steps in cam size, holley street dominator intake(will work with thermoquad), 440 source heads, headers, 3" dual exhaust and you could see some 12 second 1/4 mile times.
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Re: which heads for my 400 engine?
[Re: DaytonaTurbo]
#1823709
05/10/15 10:08 PM
05/10/15 10:08 PM
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Joined: Feb 2005
Posts: 4,316 Prospect, PA
BSB67
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Prospect, PA
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The 75 cc Eddy head mill to 70 cc will put him over 9:1. You could probably get to 9.5:1. Slapping on a 84 cc stealth head will be 8:1.
You can spend an additional $1000 to make another 30 or 40 hp with good heads, or spend $3000 on gears, converter, big exhaust, tire to make a turd feel better......
Last edited by BSB67; 05/10/15 10:18 PM.
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Re: which heads for my 400 engine?
[Re: paddel]
#1823856
05/11/15 12:15 AM
05/11/15 12:15 AM
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Joined: Oct 2011
Posts: 559 Idaho
LaRoy Engines
mopar
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mopar
Joined: Oct 2011
Posts: 559
Idaho
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It doesn't have to be complicated. There are 10,000 different things you can do to make the 400 run better, but what you have chosen will make a substantial difference in your car. The 6090 heads were designed for exactly your purpose and the 10230701 cam will work fine in your engine. If you chose to go to a 3.55:1 gear the whole combination will make the car feel like a rocket ship vs what it is now. When you learn from these few changes and later want to do the stroker, sell the heads and go to a more performance oriented cylinder head. This is a quick example of what a 400 will do with less compression, cam and airflow than you are planning. low compression 400 on the dyno
Last edited by LaRoy Engines; 05/11/15 12:22 AM.
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