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440 buildup dissapointed in HP - Help!

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440 buildup dissapointed in HP - Help!

Brian68 Brian68
New User | Posts: 1 | Joined: 05/09
Posted: 05/14/09
12:23 PM

Hello Mopar experts, I'm a newbie to the mopar world (and forum) with one 440 buildup under my belt, but with HP results that are a bit disappointing considering the parts and time I've put into the car so far.

Here's the story:
I've got a 68 charger with 440/727 and 2500 stall with factory posi (or whatever they called it back then, suregrip or something). I have recently rebuilt the engine with the following:

Balanced/bored with flex plates/4 corner decked (0 deck height)
Eagle rods (with stock steel crank)
JE pistons (fresh 40 over bore,10.36:1 compression)
Stealth aluminum heads with mild porting and port matching to intake
Weinand dual plane intake
Mightly demon 850 (running at 13:1 consistently through the RPM range)
Comp cams with 235/237 @.050 and 503 lift, 110 centerline (hydraulic)
Running 1.5 steel rockers (cant run my 1.6 rollers due to pushrod clearance issues with the stealth heads)
MSD electronic distributor and controller (timing is 14 deg initial with 34 deg full advance)
For the exhaust, I'm running the factory manifolds (cnc'ed on the exhaust ports and ported internallly) and a Tube technologies 3" system to the tips.  
Also have high volume oil pump, windage tray, high performance carter fuel pump, 8mm wires.

I dyno'ed the car last week (pump 91 octane fuel)and had a dissapointing 330 HP and 360 torque at the wheels. Power peaked at 5000 rpm. The car isn't a slouch, but I was expecting quite a bit more.

Isn't this about what you would expect from a stock 68 charger 440 RT with 727?

I would like to be closer to 400HP/450 torgue at the wheels with much more power at the higer RPM (6000+).

Does anyone have any sugestions?

Thanks much!! Grin  

marcohotrod340 marcohotrod340
Enthusiast | Posts: 470 | Joined: 09/08
Posted: 05/15/09
03:11 PM

sounds like a good combo but maybe a 1" open carb spacer, more timing advance, more rpm, what size is the manifold outlet? atleast 2.5" + extrudehone. 92 octane and maybe a bigger carb jet. car craft made 530 at the flywheel with a similer 445 with a performer rpm and 2" hookers.  

79redexp 79redexp
New User | Posts: 14 | Joined: 03/09
Posted: 05/17/09
08:18 AM

I agree, that would be a healthy number for a stock 440 rebuild, but in your case you should be in the high 4's to low 5's. Did you degree the cam? It sounds like cam timing to me. I rebuilt a 440 in my 4x4, and it ran like a dog, I didn't use all the performance parts, but had the right combo to put it at early factory specs which were 375hp/390lb. I let the engine fully break in and the power got better, but I still wasn't happy. A friend of mine in the club helped me degree my cam and it was way off. After that I was burning all 4 tires.  

darins701 darins701
New User | Posts: 38 | Joined: 06/08
Posted: 05/17/09
10:26 AM

The factory exhaust manifolds will hold it back a little. And the dual plane intake isnt the best if you want to run in the 6000 rpm range. A single plane should raise the HP peak. I think your cam could be a little bigger. Is the cam one of the newer designs or an old "muscle car" grind?
What gear ratio does the rearend have? If i remember correctly, the dyno uses the rate of speed increase of the drive drum on the dyno to calculate its numbers. Maybe a better gear would show better numbers. I'm not 100 % sure about that so talk to the tech at the dyno.
Sounds like a nice combo, very similar to what I have in my coronet.  

1970earl 1970earl
New User | Posts: 1 | Joined: 05/09
Posted: 05/26/09
07:26 PM

hey whats up i was disappointed with my 77 440 hp till it was dynoed and i got 375 hp and 518 ft lbs of torque 6900 rpms will be getting sheet end of this week cant wait till its in  

drmopar drmopar
Guru | Posts: 1445 | Joined: 02/08
Posted: 05/26/09
09:38 PM

Considering the equipment you are running the numbers are not that far off. However the torque numbers are low for a 440. To correct you need to do the following.
The 850 is absolutely over kill, unless your building a 550 hp drag motor. A good 750 DP is a better choice for a street ride.
Headers are a must and will free up 25-30 horsepower. If you are running stock valves go with 1 3/4" headers. If you have the 1.81 exhaust valves go with 1 7/8th.
Also the cam is holding you back, not enough duration, not enough total timing.
A 440 should have no less than 38 degrees total, I bet there is 15-20 horse just in setting up the timing correctly. 10-12 Initial, 38 total.
You never mentioned a gear ratio, I suspect it is a street car and you probably have a set of 3.23 or something similar. If this is the case I would leave the cam. However for best power from a hydraulic cam the mopar P5007698 is a great choice. You will need at least a set of 4.10 gears and a 10" 3500 converter if you run this cam. I would also recommend an edelbrock torqer 2 intake. The stealth heads are questionable at best, flow numbers are not even close to be considered a good high performance head. A good set of 452's ported and polished will blow these heads away.
These upgrades will put you close to 450-500 horse at the crank with about 500 ft. lbs of torque, but remember, if you up the gears you will lose some driveability.
So considering the set up you are running the numbers are fairly consistant with a near stock 440 build.
Doc Cool  

kbmadness kbmadness
New User | Posts: 3 | Joined: 02/09
Posted: 05/30/09
01:08 PM

Fuel and timing make a big difference. I had my 340 Cuda dyno, it's stroked to a 416 with a pro charger super charger. Talk about feeling bad about HP number, the first pull car made 420 hp. The guy went up 12 jet sizes and we gained 330 hp on the next three pulls. And he changed the timing too.  

marcohotrod340 marcohotrod340
Enthusiast | Posts: 470 | Joined: 09/08
Posted: 06/05/09
03:34 PM

can u grind on the heads to get clearance to run the 1.6 rockers? cuz they will help. a smaller carb will probably not help. 1 3/4" headers are for small blocks. experiment with timing advance, every combo is different, whatever makes the most power is your best number.  

drmopar drmopar
Guru | Posts: 1445 | Joined: 02/08
Posted: 06/06/09
03:19 PM

Please explain how a larger header will benifit an engine with a 1.74 exhaust valve? All a larger header will do is cause you to lose you bottom end torque.A 750 will handle 540 horse, so why lose bottom end and torque with an 850.
I put a worked 850 on my 500 horse 440 and lost a half a tenth and the car never left the same. Yes the car had all the goodies, 3800 stall, 4.30 gears and I am a licensed tech. so I can assure you I didn't have a bad carb.
The 750 was the superior carb especially for a street strip ride.
If you go to comp. cams cam quest, they have a great chart were you can see what difference a carb and headers will make. The 100 CFM extra is worth about 2-3 hp more at 6000 rpm, but you will lose 20 ft. lbs of torque at 3000 rpm.  
So you never gain back what you have lost with the larger carb.

marcohotrod340 marcohotrod340
Enthusiast | Posts: 470 | Joined: 09/08
Posted: 06/07/09
06:23 AM

Brian68 has not told us his valve size. he did say he has manifolds and wants more power at a higher rpm. he did not say if the car is for the street, the strip or both. Brian - more info please. nhra stockers and super stockers with 1.74" valves run 1 7/8" - 2" pipes. please measure the size of your exhaust ports and remember a 1 3/4" header pipe is 1 3/4" OUTSIDE DIAMETER. I have seen plenty of dyno tests where a larger carb or cam or headers increases power without losing any low end. u want the inside diameter of the pipe to match the exhaust port (or be slightly larger) not match the size of the exhaust valve. many talk about matching intake to intake port and forget about matching exh. port to pipe ID  

drmopar drmopar
Guru | Posts: 1445 | Joined: 02/08
Posted: 06/08/09
09:48 PM

Good advise, however what works on a dyno doesn't always translate into an increase in the real world.

bmanzi bmanzi
New User | Posts: 1 | Joined: 01/10
Posted: 01/19/10
02:28 PM

WORD OF ADVISE PER 1 7/8 HEADERS: super comp = super fit problems. please heed my experience
# 3 plug boot melts on booth mine and my fathers
B-Body torsion bar rattle required alot of bending / welding / gaskets
fire wall rubs

ive heard the doug headers are well worth there money per fitment and performance  

.71RedneckStroker_ .71RedneckStroker_
Guru | Posts: 848 | Joined: 11/09
Posted: 01/20/10
02:57 PM

Those are great numbers at the rear wheels. What are you wanting? To drive a drag car on the street? All of your parts sound like really good combo. I would suspect if you have 330 HP at the wheels, you probably have 450 or more at the converter. That in a 68 Charger is good for some 12s on street tires and possible 11s on slicks with a good gear. What more could you possibly want? Throw all the numbers out the window for a minute. How does the car FEEL to you? If you like it, then don't worry about it. It's too easy to get caught up in the numbers game. Too many people get obssessed with it. I'm sure your car is plenty fast enough.  

I can put a square peg in a round hole. Gimmie that hammer.

Furios66 Furios66
New User | Posts: 5 | Joined: 12/08
Posted: 01/28/10
08:19 PM

It might be worth your reading of the build up they did here for a factory hp440. They got 330 hp as stock. When up graded to a 850 carb, 1 7/8 headers, comp cam and better intake. They gained over 100 hp. This is basicaly what I was looking at for my re build. I will be running a dual quad set up. I should still pull the same numbers at the least.  

Skwerly Skwerly
User | Posts: 76 | Joined: 02/10
Posted: 02/03/10
10:05 AM

I have to agree with Redneck here; does the car do what you *want* it to?  You might, as others have suggested, want to pull back to a 750 carb and see how that works out, but otherwise 330 at the rear wheels is VERY respectable.

Remember, massive amounts of hp/torque are lost in the drive train.  The original 375 horsepower 440 engine numbers were taken at the crank, NOT the wheels.  That # will probably net you a good 250 to the ground.  YOUR numbers are much higher, and as others have said, I don't think they are too far off from what the 440 you built should be!  

Play with the timing a bit and the carb jetting.  I think you have a runner there!  Smile  

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