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Need Little Better Torque/hp From Stock 383


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11 replies to this topic

#1 Raull

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Posted November 27, 2005 at 02:41 pm

I have a 1966 2 bbl 383 low compression (9.2:1, dished pistons) engine with the relatively poor 516 cylinder heads from a 1966 Newport. The engine is blowing smoke from the head valve seals and is currently install in my 1968 Charger.

The curent modifications Ive done to it are:
I put in a Edelbrock 383 Streetmaster intake single plane,
Holley double pumper spreadbore carburator 650 cfm.

I would like to get more Torque/HP withought taking the engine out.
First Cam kit (what type?)
Bigger Carburator?

What else can I put in it to get a better boost?

#2 cavemanmoron

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Posted November 27, 2005 at 05:37 pm

The 383 2bbl used a very small cam .390 lift 252 advertised duaration.
In 1966, this was rated at 270 hp[at]4400 rpm,390 torque [at]2800

Where is the 1968 engine?
That had a much better cam,and made 290 hp
.425/.435 lift.

What gear ratio rear do you have in the car?Do you have dual exhaust,off the stock manifolds?
you should really pull the heads off and get a valve job done,and replace the valve springs at the
same time,to the springs that go with the cam you choose.

Comp cams makes a real nice lower rpm cam,i would suggest if you have
3:23 or 2:94 gears. Especially if you have the stock low compression engine,
you don't really want too large of a cam.A cam that would work well in a 440,
will not work as well in a 383.

More is not always better with a cam,nor a carb size either>I have learned this the hard way.

Don't forget that you need to replace the lifters;
and should replace timing chain/gears and the valve springs when you change a cam,
especially if the parts are original,LOL.

http://store.summitr...15&autoview=sku
Basic Operating RPM Range: 600-4,800 RPM

Advertised Duration: 250 int./260 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.432
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.444

Mopar Performance makes a couple of good cams also. :)


http://store.summitr...15&autoview=sku

Basic Operating RPM Range: 1,000-5,300 RPM

Advertised Duration: 260 int./260 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.430
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.430


If you have more info that would help,like gear ratio etc.

Do you have electronic ignition yet?thats a good idea too.

Edited by cavemanmoron, November 29, 2005 at 07:50 pm.


#3 mopodge

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Posted November 27, 2005 at 11:39 pm

Well if you want torque on the low end, velocity is important, but if you want horsepower up high, flow is important. Horsepower and torque are 2 different things so which do you want? or both maybe? both is tough at a high performance level but for the street, you will be able to have some of both but not too much of either. I would suggest a dual plain manifold for street use 1st of all. single plain is more for racing and high performance and tends to give more high rpm power at the expense of low end torque. 9.2 is not too bad of compression. If you are going to be using this car on the street, i wouldn't go any higher or you won't be able to run it on pump gas and driveability will suffer. Maybe the engine is just tired. A 66 383 should perform well but if it was a factory 2 bbl, it probably was built for family type use, not high performance. Make sure you have good dual exhaust and high-flow mufflers. That is a must if you are using a 4 bbl and high-flow manifold. Cam is defenitely a must also. You could have an 850 double pumper carb, a single plane racing manifold that's been ported for even more flow, and huge 4" dual exhaust, but if you don't have a good cam with at least .430 of lift, none of that gas and air will be able to get in and out of the engine very quickly and you will just be bogging it down and pouring gas into the oil. So have good exhaust and a good cam, then see how it performs. I bet with those 2 things, you'll gain 50 horsepower or more, depending on the cam size.

#4 Rodger

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Posted November 28, 2005 at 09:42 am

Hola

The correct subject was almost covered in the last post. Just ask around for a reasonable muffler non-national chain shop in your area. Let them know that you would like the same inside diam as the manifold to the "X" pipe and then to a set of mufflers of the same diam. If they grab a picture book, let them know it should look as the 300 except for the new tech of the "X".

The "X" will give ya better emmission readings, and if you had a dyno it would show better everything from idle to red line. If you use a dyno at every parts chance it would also show the gain or loss ( like single plane intakes with a 800 Cfm carb on a street vehicle ).

In a place as this site you will get all types of dream builds. Ask around about giving the 383 the 1968 HP spec's. Call NAPA's machine shop and tell them this same info and get the price. MoPar Performance sells a head porting template. Call their number at: 1-248-969-1690 and they will give you an idea of the HP the 383 would have if built as above.

Remember the high reving rpm's will not move the sled as torque will from 0 to 60 mph.

Rodger & Gabby
Colo Spgs

#5 Rodger

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Posted November 28, 2005 at 10:09 am

Hola

After I punched the key I realized that MoPar Performance had a new phone number of: 1-888-528-4364. Even with the non HP exhaust manifolds, but with the "X" you should get around the 335 HP area and 425 pounds of torque. Not bad from the 270 /390 spec's that you started off with.

ps
keep the same size of valves that you now have.

You need stump pulling torque .

Rodger & gGabby

#6 Gibons

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Posted November 29, 2005 at 06:13 pm

When choosing a cam there are a lot of variables to consider not just the total duration actually the total duration you should ignore altogether because its rated differantly by differant companies. I'd go with a Comp Cams, Crane Cams or Mopar performance. I'd stay away from eddy cams they make good intakes etc but I'd stick with an actual Cam company. I've had good luck with Comp Cams personally. You want a performance boost from what I Could tell so personally if I was you I'd probably use The Comp Cams XE 262 It has 218 degrees duration intake side at 50 thousands and 224 exhaust. .462 lift intake and .470 exhaust and a 110 degree's lobe seperation I'm pretty sure you'd be really happy with the hp increase especially when you get above about 3000 rpm to 5600-6000. You might notice a slight lope at an idle with this cam but nothing that should serously hurt driveability.

Edited by Gibons, November 29, 2005 at 06:22 pm.


#7 cavemanmoron

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Posted November 29, 2005 at 07:21 pm

When choosing a cam there are a lot of variables to consider not just the total duration actually the total duration you should ignore altogether because its rated differantly by differant companies. I'd go with a Comp Cams, Crane Cams or Mopar performance. I'd stay away from eddy cams they make good intakes etc but I'd stick with an actual Cam company. I've had good luck with Comp Cams personally. You want a performance boost from what I Could tell so personally if I was you I'd probably use The Comp Cams XE 262 It has 218 degrees duration intake side at 50 thousands and 224 exhaust. .462 lift intake and .470 exhaust and a 110 degree's lobe seperation I'm pretty sure you'd be really happy with the hp increase especially when you get above about 3000 rpm to 5600-6000. You might notice a slight lope at an idle with this cam but nothing that should serously hurt driveability.



Hmm that cam you suggest might be nice if he has 3:55 or steeper gears,
and would be even better in a 440.

the cam I suggested has a lot more torque at bottom end,
That is another reason, why I said,what gears etc.

CCA-21-222-4 {XE 262}

Operating RPM Range: 1,300-5,600 RPM

Don't forget he is using the Low compression 2bbl engine.
If he drives the car on the street,he prob will not be reving the engine to 5,000 rpm. ;)

CCA-21-220-4 {XE 250}

Basic Operating RPM Range: 600-4,800 RPM
http://store.summitr...15&autoview=sku



Lee

#8 Gibons

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Posted November 29, 2005 at 07:29 pm

Ya that would be a nice daily driver cam. You'd probably be ok with the Cam I suggested if you had 3.23 or so gears its a little hotter than the stock 383 magnum cam. He could also compromise and go for the.

XE 256 right in the middle.

#9 Bearhawke

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Posted November 29, 2005 at 07:57 pm

Ya that would be a nice daily driver cam. You'd probably be ok with the Cam I suggested if you had 3.23 or so gears its a little hotter than the stock 383 magnum cam. He could also compromise and go for the.

XE 256 right in the middle.


The classic MoPar Magnum cam was pretty strong in the 440's............and, the 383 V8 being smaller, that same cam would be rather wicked. :D

#10 Gibons

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Posted November 29, 2005 at 08:42 pm

He did say he already put a single plane intake in it to I just realized if he was going for low end torque he would have put a low profile duel on not a hi-rise single. He'll need more cam to utilize it.

#11 fred2

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Posted December 3, 2005 at 10:07 pm

I have a 1966 2 bbl 383 low compression (9.2:1, dished pistons) engine with the relatively poor 516 cylinder heads from a 1966 Newport. The engine is blowing smoke from the head valve seals and is currently install in my 1968 Charger.

The curent modifications Ive done to it are:
I put in a Edelbrock 383 Streetmaster intake single plane,
Holley double pumper spreadbore carburator 650 cfm.

I would like to get more Torque/HP withought taking the engine out.
First Cam kit (what type?)
Bigger Carburator?

What else can I put in it to get a better boost?

Rebuild the heads, go to 1.74" exhaust valves (from 1.60") and hardened seats and perform a mild porting job. While you have the heads off, put in a new cam. A dual exhaust will also help. I think that you should go to a dual plane intake, many of the later (1968 and later) factory 4 bbl intakes worked fine and are cheap. What are you running for an ignition? Points stink. Get an electronic set up of some description. Pertronix is about the cheapest using your present distributor for about $70. It is just up from there. The Mopar distributors and Orange ECU are good for about $200. Watch out for the vacuum advance curve. It could be to aggressive for your engine if you go with a new distributor. The coil is also important. I think that your carb is big enough. Look at other things first. Good luck.

#12 Rodney

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Posted December 4, 2005 at 10:27 am

I have a 1966 2 bbl 383 low compression (9.2:1, dished pistons) engine with the relatively poor 516 cylinder heads from a 1966 Newport. The engine is blowing smoke from the head valve seals and is currently install in my 1968 Charger.

The current modifications I've done to it are:
I put in a Edelbrock 383 Streetmaster intake single plane,
Holley double pumper spreadbore carburetor 650 cfm.

I would like to get more Torque/HP withought taking the engine out.
First Cam kit (what type?)
Bigger Carburetor?

What else can I put in it to get a better boost?


A 440 engine B)
ok that's always been my fix more cubic inches.
if you are spending the money to rebuild or buy parts start with a good foundation. it may cost a few more dollars for 440 parts but you will have a much better result.
All of the advise given is right on,
choosing a cam shaft is one important thing to consider guess what I don't see you telling us What transmission is in your Charger? {maybe I missed this in other posts?} 727, 4 speed ect?
gear ratio?
tire size?
weight of car?
I would guess around 3500 lbs without driver. by the time you add driver a passenger or 2 full tank of gas ect. 4000 lbs could be closer.
If you are truly starting with an old 383 that hasn't been taken apart that you know of how can you expect to gain any real improvement without starting with a fresh engine?
you do head work and increase the pressure in the cylinders you are looking for failure in the bottom end
blow by the rings, and if the bearings are OEM they should be replaced and don't forget the cam bearings.
The single plane as mentioned before is not helping you any right now and is hurting your bottom end power in your case.
as said before smaller is better.
small 4 bbl on a dual plane intake
1 7/8 headers
dual exhaust
ect.
but none will do you much good on a wore out engine.
The valves have to seal the cylinders and pistons have to be round for a good seal
before you can expect to make any engine improvements.
torque converter if an auto should be rebuilt or change to fit your application.
transmission needs to be in good working order and set up for your application.
axle ratio should be 3.23's or better depending on tire size ect.
just don't spend to much effort if you don't know what you have inside the 383 or you will be doing it in vain.
good luck B)


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