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I understand that the MP grinds are old tech but its proven technology that works. My dad is running what I think is the comp cam XE268, it is a .540 lift cam with 280 duration in his 67' Dart GTS that has a built 440.

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The XE268 hydraulic has slightly different numbers than that...
http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=707&sb=2

I think the XE268H Comp Cam would be a good choice for your 383 truth be told.

Don't get me wrong, I really like the MP 235 camshaft (old version 484) and have ran it it dozens of engines, I'm one of the few guys who really likes it probably but I really think it's going to be more cam than you think in a 383.

I'm building a 9.35 to 1 compression 440 right now and almost went with the 484, but I ended up going with a Comp Cam 270H grind. Probably a bit on the mild side but I want a very drivable car, and I have 446ci, AC and 2.88 gears with 26" tall tires...



I've never tried the newer MP 484 cam, I assume it has a wider LSA or?

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I'm open for opinions, just don't want to be bashed on cause I have a different opinion than everyone else.

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So does anyone use the MP cam now? And how many of you guys actually used one of these cams in the past, minus those who provided a direct experience (Thanks again). I want opinions from people who have actually used the MP cam, not people who have never used it telling me that its a 30 year old design. Another thing is that not every guy who owns a mopar built their motor perfectly. It's easy for someone to put in the wrong pistons, intake, carb, etc. and blame it on the camshaft.

And if the MP products are so bad, then why are they still manufacturing and selling them? There must be consumers out there who think their products are worth it.

Somebody please tell me a simple issue of why the MP cams are so bad. Is it too much overlap, lift, duration, or was the mopar world tired of MP cams and decided to just go and try other things?

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From what I understand, when running factory exhaust manifolds, you’re better off with a 112-to-114 centerline.

Also, as already mentioned in this thread, go with a custom cam for your application.

In my 383, I’m going with a Mr. SixPack custom grind from Engle Racing Cams which is designed by Bob Karakashian. The cost is a bit more than an off the shelf cam but worth it. $235.00 to your doorstep and that dose not include lifters.

But that cam has bone stock 440-6s running in the high 11s on factory polyglass tires. You might be able to get the ETs you’re after with you're 383.

You can give Mr. Karakashian a call and he’ll talk it over with you.



Mr.6Pack Racing Engines - link

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Random question, how old are you guys?

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I missed this!

I'm an "old enough to know better, young enough to do it again and again, and again" ..... kinda guy!

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Random question, how old are you guys?

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I missed this!

I'm an "old enough to know better, young enough to do it again and again, and again" ..... kinda guy!

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Does the LSA play that big of a factor when using either headers or manifolds? The LSA on that 280 grind is 110* but I know that new 284 MP cam has 114 LSA along with the previous one that had 108* or so LSA.

That sucks that performer RPM intake doesn't clear cause I do plan on using the factory air cleaner. Has anyone used that M1 dual plane intake before? It looks kinda like the stock intake so I'm curious if the runners are larger and better air flow?

PS I'm the young gun

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I've never had a newer 484 cam with the larger LSA, but I assume it was done for drivability. Maybe somebody who has used one could chime in, I have only used the old 484.

The M1 intakes are good, I even have one on my motorhome. Better flow for sure, but it depends on which M1 intake.

I was a young kid working on cars and driving junk back in the late 70s!

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So does anyone use the MP cam now? And how many of you guys actually used one of these cams in the past, minus those who provided a direct experience (Thanks again). I want opinions from people who have actually used the MP cam, not people who have never used it telling me that its a 30 year old design. Another thing is that not every guy who owns a mopar built their motor perfectly. It's easy for someone to put in the wrong pistons, intake, carb, etc. and blame it on the camshaft.

And if the MP products are so bad, then why are they still manufacturing and selling them? There must be consumers out there who think their products are worth it.

Somebody please tell me a simple issue of why the MP cams are so bad. Is it too much overlap, lift, duration, or was the mopar world tired of MP cams and decided to just go and try other things?

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I had the 484(108lsa) in a low squeeze 383,4spd,3:23 A-body. Idle sounded wicked,but drivability sucked! Driving thru a parking lot with long gears and a big cam is a real treat.
It's not so much that MP cams suck(though there are QC issues and yes I know plenty of guys that "lost" lobes)just there are MUCH better designs out there now!Why not take advantage of 30 yrs of design improvements?I've got a solid roller now that idles better and pulls harder than that old MP design!Do the research...the cam companies have!

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On one side there is guys standing by the new cams being produced while on the other side are the old crusty mopar guys that stand by the MP cams.

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And we haven't even touched on asymetrical lobes and dual pattern grinds!

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And we haven't even touched on asymetrical lobes and dual pattern grinds!

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I think the lack of ZINC should be mentioned too!!!!!

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And we haven't even touched on asymetrical lobes and dual pattern grinds!

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I think the lack of ZINC should be mentioned too!!!!!

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Think he's ready for the roller cam consideration???

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NO!!

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If you read everything else I posted its not a stock rebuilt 383. The only thing thats gonna be stock is the block itself and the hi-po manifolds, thats it.

I already listed everything that won't be stock such as the stealth aluminum closed chamber heads, the performer rpm or M1 dual plane intake, the carter comp carb, raising the CR to 9.5:1, converting to a 3.55 gear. I dont know how in the world all of this is a stock rebuild for a 383. The only draw back to the whole set up is keeping the AC pump. Other than that I have manual brakes so vacuum doesn't mean a thing to me and a 4 speed which means no torque converter issues either.

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The original 284 cam (2035) has low vacuum so if no power brakes you should be fine. However your mentioned Carter 750 carburator, I would recommend a Holley as the Carters/Edelbrock don't like low vacuum and are difficult to tame the idle. Has to do with their metering rods and pistons design.. Besides a Holley is just simpler and EZ to tune..

Just my $0.025..

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If you read everything else I posted its not a stock rebuilt 383. The only thing thats gonna be stock is the block itself and the hi-po manifolds, thats it.

I already listed everything that won't be stock such as the stealth aluminum closed chamber heads, the performer rpm or M1 dual plane intake, the carter comp carb, raising the CR to 9.5:1, converting to a 3.55 gear. I dont know how in the world all of this is a stock rebuild for a 383. The only draw back to the whole set up is keeping the AC pump. Other than that I have manual brakes so vacuum doesn't mean a thing to me and a 4 speed which means no torque converter issues either.

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The original 284 cam (2035) has low vacuum so if no power brakes you should be fine. However your mentioned Carter 750 carburator, I would recommend a Holley as the Carters/Edelbrock don't like low vacuum and are difficult to tame the idle. Has to do with their metering rods and pistons design.. Besides a Holley is just simpler and EZ to tune..

Just my $0.025..

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The original 284 duration 484 MP cam was part# 4120235, it had vacuum depending on the application.
My Demon was a 484 cam, it had a tunnel ram and a small pot power brake reservoir, I had no problems whatsoever. TONS of vacuum for the brakes....

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From what I understand, when running factory exhaust manifolds, you’re better off with a 112-to-114 centerline.

Also, as already mentioned in this thread, go with a custom cam for your application.

In my 383, I’m going with a Mr. SixPack custom grind from Engle Racing Cams which is designed by Bob Karakashian. The cost is a bit more than an off the shelf cam but worth it. $235.00 to your doorstep and that dose not include lifters.

But that cam has bone stock 440-6s running in the high 11s on factory polyglass tires. You might be able to get the ETs you’re after with you're 383.

You can give Mr. Karakashian a call and he’ll talk it over with you.



Mr.6Pack Racing Engines - link

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Been running Bob's Mr. Sixpack cam for 3years now... I pulled an MP .484 out of my 9.6:1 383... I run 3.23's (currently) and manifolds, FWIW, I wouldn't run that MP cam in anything less then a 440 in a B-body too much weight

Very happy with the Engle/Bob K piece

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...FWIW, I wouldn't run that MP cam in anything less then a 440 in a B-body too much weight

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It sucks to have to go back and tear the whole engine apart to replace a cam. I've already figured that out on my malibu when I used an Iskey cam that had waaaay too much duration.

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Did you have a resource such as Moparts for that deal? Did you wave off any veteran Chevy guys to do "the young gun" thing?

We aren't here to argue you, just to help you. Most of us have been there and done that. I had the 484 cam in a 71 Cuda. It was at the very edge of being OK in that car with a 440. You have a heavier car and less cubes. But wy bother to tell you anything, you just want to joust with us so...

Go ahead with what you want. You knew what you wanted before you came on here. You don't need us. You have some old dusty books. You want to prove those that have been there and done that wrong, go ahead and give it a shot. It is your money. Carry on...

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That is why I opted to go with the 280 instead of the 284 if I get a cam from MP.

I'm looking at other cams though because the main thing I'm seeing with the 280 grind is that its powerband is from 2000-5900 rpm for "mild compression applications". Now if I raised the compression by going with a flat top piston and some mill work on the heads, would the power curve kick in at a lower rpm than 2000? I also spoke with another guy that told me the CR of the 383 out of the factory was 10.25:1. Anyone agree with this statement?

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Not even close! My virgin numbers 383"HP" '70 block was a mile in the hole! I bet I had MAYBE...MAYBE 9:1

I really like the Lunati Voodoo series(others here do too.) I have one in a stoker 451 and just order one for a blown street 413 build

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That is why I opted to go with the 280 instead of the 284 if I get a cam from MP.

I'm looking at other cams though because the main thing I'm seeing with the 280 grind is that its powerband is from 2000-5900 rpm for "mild compression applications". Now if I raised the compression by going with a flat top piston and some mill work on the heads, would the power curve kick in at a lower rpm than 2000? I also spoke with another guy that told me the CR of the 383 out of the factory was 10.25:1. Anyone agree with this statement?

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What year 383?
The pistons (all flat tops regardless of compression from the factory, I think anyways.. ) need to be physically measured to see how far down the hole they are. Some are above deck on a 383 if I remember correctly... (correct me if I'm wrong guys!)

Most ratings weren't very accurate. The compression ratios, head cc's etc that were published weren't always bang on, more times than not they were wrong!

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Just don't tell us that it is tried and true and must be beaten to be dethroned as king- because it has been already.

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I didn't say that though on any post... I just said it must be a decent cam if it is still on the market and mopar guys are still using them. No need for you to stir up an arguement.

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First, I didn't know what cam I wanted before I came to this site. I'm not jousting or whatever you may think I'm doing here. I'm trying to learn all aspects of a cam and how the motor will behave when certain things are changed such as heads, CR, etc.

Second, not every person on this site is the dubbed "The Master of Mopar" or the brightest bulb in the box. Yeah I'm a young gun, and I'm learning.

Now I'm taking down all the cams and specs and coming up with different set ups with my RR. Those "old" dusty books hold many a secrets from the racing days when Mopar, Chevy, and Ford were duking it out on the track. ]


This IS what I plan on going with as far as parts, WITHOUT the decision of a cam:

-3.55 rear gear
-Stealth aluminum heads
-M1 dual plane intake (Eddy RPM performer wont clear my factory hood)
-flat top pistons
-factory 4 speed
-9.5:1 to 10:1 CR
-Carter Comp Carb or another possible variant that retains the factory look of a mopar carb

Hopefully this will clear up any confusion with previous posts. Basically, I don't need the fastest car on the block. Roadrunner's are pedigree cars that don't need to hall a** anymore to prove themselves. I just want something that drives great and once in a while spank the ocassional ricer that has an ego.

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Just don't tell us that it is tried and true and must be beaten to be dethroned as king- because it has been already.

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I didn't say that though on any post... I just said it must be a decent cam if it is still on the market and mopar guys are still using them. No need for you to stir up an arguement.

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And that is exactly what MP want's you, and others to think... it doesn't cost them a dime to sell the same grinds they have for years! Let's be honest... some feel a real loyalty to MP! Too bad they have not maintained the same loyalty to US... if they had we wouldn't be using 1970's cam grinds There are better..much better out there now

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Just don't tell us that it is tried and true and must be beaten to be dethroned as king- because it has been already.

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I didn't say that though on any post... I just said it must be a decent cam if it is still on the market and mopar guys are still using them. No need for you to stir up an arguement.

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You're right greenhorn, YOU started the arguement when you first came on here with the whole thread to begin with. Anybody not worshipping the MP junk is a fool in your eyes. So just run what you want, this is the internet, nothing to take very seriously.

BTW, I left the stock cam in my 383 RR when I had a chance to ditch it. So I'm still running an old tech cam myself.

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You're right greenhorn, YOU started the arguement when you first came on here with the whole thread to begin with. Anybody not worshipping the MP junk is a fool in your eyes.

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You're right greenhorn, YOU started the arguement when you first came on here with the whole thread to begin with. Anybody not worshipping the MP junk is a fool in your eyes.

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You must be reading a playboy when your typing this cause you sure aren't reading the posts on this thread. Yeah I'm a real greenhorn after building 6 engines. I don't think there is anything out there to tell if someone is a greenhorn or expert doc.

Now I have been inputting and changing data into camquest for the past couple hours. The MP cams were a good line of cams to work around. Some of you were right that the 284 MP would be overcam for my 383. The 280 grind I had suggested before was right at where Comp cams is suggesting their line of cams.

The difference between the two is that comp cams has a shorter duration on the intake rather than have the duration the same for intake and exhaust.

The two cams Comp showed that would give me the best torque and hp numbers were the XE262 and XE268H. The XE262 would give me 380hp and 440lb. while the XE268H would give me 390hp and 430lb. So which would you guys go with? Torque or HP?

BTW the set up consisted of using a set of ported 346 heads, dual plane high flow intake, 750 cfm carb, 9.5:1 CR, and HP manifolds.

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The two cams Comp showed that would give me the best torque and hp numbers were the XE262 and XE268H. The XE262 would give me 380hp and 440lb. while the XE268H would give me 390hp and 430lb. So which would you guys go with? Torque or HP?

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With the camquest program, I can actually see what the car is going to be doing rather than trying to put cam names on a dart board. What's gonna be hard is trying to find a car that has a nice choppy to mild rough idle cause I know the good torque producing cars are low lift and don't have a very radical idle as say the other guy in the 500+ lift range.

Another thing, I'm heading out to the junkyard here in a few and am gonna be looking at heads. I know there's nothing wrong with my 346 heads, but if I come across a set of 915 or 516 heads you think it would be a better thought to go with closed chamber rather than open chamber heads?

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Didn't you just post 12 hours ago that you were going with Stealths???

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-3.55 rear gear
-Stealth aluminum heads
-M1 dual plane intake (Eddy RPM performer wont clear my factory hood)
-flat top pistons
-factory 4 speed
-9.5:1 to 10:1 CR

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With the camquest program, I can actually see what the car is going to be doing rather than trying to put cam names on a dart board. What's gonna be hard is trying to find a car that has a nice choppy to mild rough idle cause I know the good torque producing cars are low lift and don't have a very radical idle as say the other guy in the 500+ lift range.

Another thing, I'm heading out to the junkyard here in a few and am gonna be looking at heads. I know there's nothing wrong with my 346 heads, but if I come across a set of 915 or 516 heads you think it would be a better thought to go with closed chamber rather than open chamber heads?

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Didn't you just post 12 hours ago that you were going with Stealths???

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That's why I stated this thread is all over the place!Now he wants a rough idling cam that makes good torque is a 383? I think it's time to sit this one out,I'll just spectate

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Does the LSA play that big of a factor when using either headers or manifolds? The LSA on that 280 grind is 110* but I know that new 284 MP cam has 114 LSA along with the previous one that had 108* or so LSA.

That sucks that performer RPM intake doesn't clear cause I do plan on using the factory air cleaner. Has anyone used that M1 dual plane intake before? It looks kinda like the stock intake so I'm curious if the runners are larger and better air flow?

PS I'm the young gun

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No, the data I put into camquest was using HP manifolds. I want to keep the motor looking stock and give it a lot more than what the factory was giving.

With a 3.91 gear, wouldn't that be too much gear? I've seen how easy it is to break traction with a stick. Another issue with the 71' b bodies is that there is hardly any weight in the rear and is hard to get good traction. An owner of a 71' charger told me this and also said there was a brick weight that the factory put on some cars right above the axle housing in attempt to get better traction. This brick weight was only 25lb. though.

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I think the brick weight is a tall tale myself...


Closed chamber heads can be thought of as different things I guess, because the Stealth heads are in the 84cc range...
The aluminum will have to be accounted for as well as it will remove heat from the combustion chamber more than an iron head. I think the Stealth heads should have had a slightly smaller chamber to be considered "interchangeable" with iron heads for comparison purposes....

Don't use ANY kind of computer program as gospel. They will give good ideas, and general answers, but many can be wrong, tricked, and if the input isn't exact the outcome of the computer program won't be exact either.
Enter a compression ratio "as claimed" would be a guess IMO, and not an exact figure.
Same goes for head flow, combustion chamber cc, etc...

You can search for answers for a month before choosing a cam, and while you will most likley be ballpark in what you end up with, the experience will help you choose the next cam. And so on...

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Cuda, wouldn't a set of 915's work just as good as stealths? The only difference is the weight. It would be nice to have a set of 915 or other closed chamber head on the side in case finances fall through for the stealth heads. I'm still leaning towards stealth because I'm keeping the AC so it will help compensate for that.

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And who doesn't want their car to have a nice sound at idle? Comp cams claimed that the XE262 and XE268H both have choppy to mildly rough idles, so I'll just take their word for it.

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you have posted on here all about different things regarding your motor. You haven't addressed the driveline and chassis at all. you are gonna need Caltracs, subframe connectors, torqueboxes and good axles. Blueprint your frontend; go to manual steering and you are definitely going to need more than 3.23s to achieve your et goal. Even, even, EVEN IF your engine cranks 400 horses at the flywheel, you need to remember MoPar built cars as packaged vehicles; THAT was the secret to success in the 60's. you aint building a shivverlay, so throw that stuff out the window. Build your motor like you say you want to, and then we will help you find the 2 seconds of et you are missing.

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I know the rest of the car needs to be brought up to specs with the engine once it's done. The car is already manual steering from the factory so I'll just check that off the list . As i mentioned before, I think the 3.55 or 3.73 gear is a good top and bottom gear, and what spline axles did the b bodies come with in those sure grip rear ends?

As far as the sound goes, if it has a nice roar to it thats fine. I'm not going for the dragster idle cause the motor won't be designed for that. I'm looking at getting more torque while getting the hp at 400 at the fly wheel. And why do 383 motors like to rev? I've heard that line a lot here on Moparts.

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You're right greenhorn, YOU started the arguement when you first came on here with the whole thread to begin with. Anybody not worshipping the MP junk is a fool in your eyes.

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You must be reading a playboy when your typing this cause you sure aren't reading the posts on this thread. Yeah I'm a real greenhorn after building 6 engines.

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