Purple Shaft 280/280 cam

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i agree with the above post.id run a little smaller with your combo.also,what kind of idle are you looking for?you heard the clip of DJV CUDA.its got a pretty healthy lope,and thats in a 360.the idle would be rougher in a 318.a custom grind is worth the extra $ imo,schneider,and isky have made me a few,been happy with the results .
 
This Comp Cams Nostalgia Series cam is almost identical to the Purple shaft. I bought it and didn't use it, if you're interested. Here's the specs:
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 2,500-6,400
Intake Duration at 050 inch Lift 239
Exhaust Duration at 050 inch Lift 246
Duration at 050 inch Lift 239 int./246 exh.
Advertised Intake Duration 284
Advertised Exhaust Duration 291
Advertised Duration 284 int./291 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.484 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.484 in.
Valve Lift with Factory Rocker Arm Ratio 0.484 int./0.484 exh. lift
 
The idle could be a little more rought than the Cuda. Certainly will be less than the 284, and that's what I expect! I have two buddies running the 284 on 318's, and I want a little more bottom end and a smoother idle.
 
If you want a noticeably better idle and more low end torque than a 284/484 cam you need to totally quit thinking about the 280/480 cam. Did you here how it sounded on DVJ's 360? It'll be quite a bit more rough on your low comp. 318. It sounds like your telling yourself there's alot of difference between the cams when there is hardly no diff. at all. 3 degrees at .050" and .010" lift is nothing. Instead of idling at 1000 rpm with 4 inches of vacuum with the 284/484 it'll idle at 950 rpm with 4.5 inches of vacuum and have maybe 10 lbs. more torque max. Now you can believe this or not. That's your choice. But I'd bet the farm you'll have a pig down low with that cam in your 318. If you truly want more low end torque and better idling you need to consider a different cam.
 
if you convinced you want to run a purple cam in you combo id run the 268/272 450/455 lift 110 lsa.jmo.if your looking for a lopey idle and still keeping it streetable go with a consevative grind with a narrow lsa,like an isky 270 mega (270/270 465/465 108 lsa) or maybe a comp 262XE.ive run the iskys with good results.never personally run the comp extreme energy grinds,but have heard good things about them.
 
Well, I will think about all those options, and talk with the guy who will build the engine. He is an expert in sb's, with almost 30 years working on it. He really likes the purple shafts, he says "It's hard to tune, but is good as hell".

I will consider all opinions here, you guys helped me a lot. But I really trust the engine builder, he has made lot's of nice engines, including the 360 I posted here.

I would like to see more vids, if possible. :-D
 
Well if I may,I bought the P#4452992 for my 360,it is in haveing the bottom end rebuild right now.My engine loves the purple cam also he is old school so maybe thats why he likes it.Any how what about valve springs what did you pick,I ask because I will doing that soon.
 
I didn't bought the valve springs yet. I will rebuild the engine about january or february, and probably the engine builder will buy that for me.

When your engine get ready, tell me your impressions here!

thanks
 
Sound great thing is everyone that ups a sound video are all in Park.I would love to here the 474 in drive with your foot on the brake.
 
Marcelo Dart BR said:
mullinax95, I've already seen your video. Really nice car! The idle is a little too fast, isn't?
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Got the same cam in my 340. High idle is the only way to keep it at a stable RPM. This cam makes only 9" of vacuum. Also, calling it a 280 is misleading. It's really 288 @ .006", which is the SAE way to measure seat duration.

I've said it before and I'll say it again. These MP cam designs are dinosaurs and you can make way more power with better driveability with a modern grind.
 
Marcelo Dart BR said:
mullinax95, I've already seen your video. Really nice car! The idle is a little too fast, isn't?
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I guess you can say that. It's set at 900 RPM. It has a 4-speed manual trans and has 11" vacuum at idle. I could drop it down I suppose but the car responds better with it a little on the high side when pulling off from a dead stop. I have since fine tuned it since the video in which I retarded the timing a bit and added larger air bleeds. It runs better than it ever has.
 
Streetability really boils down to tuning and what a person likes.I know of several people inlcuding my brother that run cams with around 5in. of vaccum at idle and they perform excellent on the street,we make a cruise to the beach (2hr. drive) every year and its done great for the last five years and knocks down 16mpg.The right initial with a good hot ignition system,good cooling system and the correct carb cfm/settings will do wonders for a nasty cam.Im not saying these cams are ideal but no ones going to lose double digit horsepower going from one grind to another with similar .050 timing events,so its what you desire in a camshaft.Just make sure you have enough compression,cubes and stall/gear to support it when looking at different grinds because thats how you want to pick your duration at .050,lobe seperation is really secondary and can be used to pick the cams idle characteristics and where the powerband/sweet spot is for the duration.
 
Good news!
I've changed my mind and bought a set of roller rocker arms and a solid cam, the mopar P4120653. It's 241/241 duration @.050", .538" lift and 112 lobe center. I've seen some cars with this cam, it has a pretty good idle at 550-600 rpm, and make way more power than the P4452992.
 
That is a very low idle. About 100 - 150 to slow even for a stock cam/engine. They need to bring it up. 700 - 750 min.!
 
The problem with all these cars sounding so radical is the carbs and total timing are not adjusted correctly.
I have run the .474 cam, and if you run a 6.5 power valve in your carb ,you will have a motor that is loading up at idle.(6.5 is stock for holley carbs)
Also the timing needs to be correct.34 total or more.
I had a 6.5 in my 360 when i first got it running and you would swear it was a funny car.
If you go a little more then half your vacume reading it does not hurt a thing.
If you run a 3.5 power valve with the .474\.484 cams and set your timing at 36 total it will idle perfect.
Run a 35 pump shot to start.BIG CHANGE IN THE CARS IDLE AND PERFORMANCE FROM A DEAD STOP TO FULL PEDAL.
Also these cams need the total timing in by 2200 rpms, so use a mopar performance set of distributor springs.
I have run both cams in my 360.
I HEARD DJVCUDA'S VIDIO AND SPIT OUT MY COFFEE BECAUSE THATS THE WAY MY 360 RAN THE DAY I STARTED THE MOTOR ,BEFORE ANY ADJUSTMENTS WHERE MADE.
If he makes the changes i have given here to his car, it will be a total differant animal.
The car no don't sounds mad and ratty ,and is better at high rpm's as you can see by the vidio, but he's leaving a bunch of torque and horse power in the tool box.
If he does take my advice after he reads this, and makes the changes ,the car will be so snappy you won't be able to keep the rpm,s down.
I hope he has a rev limiter.:sad7:
 
I HEARD DJVCUDA'S VIDIO AND SPIT OUT MY COFFEE BECAUSE THATS THE WAY MY 360 RAN THE DAY I STARTED THE MOTOR ,BEFORE ANY ADJUSTMENTS WHERE MADE.
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If he does take my advice after he reads this, and makes the changes ,the car will be so snappy you won't be able to keep the rpm,s down.
I hope he has a rev limiter.
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in djv's defense those videos are years oldl and were taken right after the swap and pretty much the first time the car ran outside the garage.. he has tweaked the carbs since then. now it sounds lumpy when the motor is cold but once warmed up it smoothes out and idles very good. the car runs mid 12's and gets like 16 mpg so he has it dialed in pretty good.

any combo needs to be tuned. you forgot about initial timing. you can have the total perfect but if the initial is off it canl idle like crap be hard to start..etc also. then the actual curve of the dist may need to be tweaked also. you don't want that total coming too early or too late either. so you may not only have to tweak the carb but you may have to play with the dist some too.
 
Hey abodyjoe,
Glad to here his car runs great.
I run my stock distributers with the vacume advance off and then turn up the total timing to 34 or higher.
The distributer can be recurved if the motor wants it due to how it's built and going to be used.( a msd distributer comes with all the differant cams
so this can be done)
Most of the time in drag racing ,i have found that adjusting the total timing and making sure it's all in, by the stall speed of your converter works best for drag racing.(this is done by using light weight springs)
This also gives the highest flash rpm for your converter.
Hitting the converter with the most torque possible out of the hole is the best way for the fastest 60 foot times.
The vacume advance on a stock engine gives the engine more initial timing and improves the way a stock motor runs at idle.
THIS IS ONLY USED FOR STOCK MOTORS.
When running a high performance motor and running more total timing YOU SOULD UNHOOK THE VACUME ADVANCE BECAUSE YOU WONT NEED IT.
The car will start fine and run smoother at idle after setting the total timing higher.
Theres no need for the initial timing like before when the total was less.
When you change the total timing ,and make it higher then the stock setting, you could run into DETINATION PROBLEMS USING THE VACUME ADVANCE AFTER SETTING THE TOTAL TIMING.

Alot of cars at the track will lock there distributers out and set there total
timing.What this means is ,they are not even using the weights in there distributers and there timing never changes.
Locking out the distributer will make a motor HARD TO START, and i would not do this for a street car, but even some hard core street people do this.

This is why you install light weight springs in your distributer and use the weights in the distributer to advance the timing as the rpms increase.THIS DOES NOT MAKE THE MOTOR HARD TO START.

Another thing they do is lock out the vacume advance so the timing is more stable at higher rpms.
The vacume advance rod can move around at high rpms and cause your timing to move around with it.
This is why msd high performance RACE DISTRIBUTERS don't have a vacume advance.
Msd distributers can be made to have the total timing come in at many differant rpms ,so you have many choices.(If you need them)
This is good for cars that are running high compresion and there motors are prone to detinaion and they want less timing at lower rpms while under a high load and more at higher rpms to gain more horse power when detination is less likely to happen.

If a street motor is build with the correct compresion for pump gas,it will not need anything but the total timing set for the most power.
MOST PERFORMANCE MOTORS WANT ALL THE TIMING THEY CAN GET AND THE INITIAL TIMING IS NOT EVEN PART OF THE TUNE.:thumrigh:
 
T67POWER said:
Hitting the converter with the most torque possible out of the hole is the best way for the fastest 60 foot times.

True.
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The vacume advance on a stock engine gives the engine more initial timing and improves the way a stock motor runs at idle.

Only if you have it hooked up IMPROPERLY to full time vacuum. If it's hooked up to ported vacuum it does not affect initial timing at all.
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THIS IS ONLY USED FOR STOCK MOTORS.
When running a high performance motor and running more total timing YOU SOULD UNHOOK THE VACUME ADVANCE BECAUSE YOU WONT NEED IT.
The car will start fine and run smoother at idle after setting the total timing higher.

I do not agree. Initial timing has a direct link to idle quality.
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Theres no need for the initial timing like before when the total was less.
When you change the total timing ,and make it higher then the stock setting, you could run into DETINATION PROBLEMS USING THE VACUME ADVANCE AFTER SETTING THE TOTAL TIMING.

If the vacuum advance is properly hooked up to the ported vacuum outlet on the carb and TUNED PROPERLY rarely will it cause detonation. My car is a perfect example. If I have any more than 35 degrees total timing with the vacuum advance unhooked it will spark knock. I just customized a dist. USING vacuum advance that provides an additional 18 degrees of timing under light throttle (via the ported vacuum port). It does not spark knock, idles better cold because on the fast idle cam it's allowing vacuum to pull the advance canister, gets 3-4 mpg. gallon better, and the spark plugs run cleaner.
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Alot of cars at the track will lock there distributers out and set there total
timing.What this means is ,they are not even using the weights in there distributers and there timing never changes.
Locking out the distributer will make a motor HARD TO START, and i would not do this for a street car, but even some hard core street people do this.

True, and I would never do this on a street car either unless it had an electronic retard device.
Click to expand...

This is why you install light weight springs in your distributer and use the weights in the distributer to advance the timing as the rpms increase.THIS DOES NOT MAKE THE MOTOR HARD TO START.

Another thing they do is lock out the vacume advance so the timing is more stable at higher rpms.

The vacume advance rod can move around at high rpms and cause your timing to move around with it.

How is that possible? There's no vacuum there at wide open throttle.
Click to expand...

This is why msd high performance RACE DISTRIBUTERS don't have a vacume advance.
Msd distributers can be made to have the total timing come in at many differant rpms ,so you have many choices.(If you need them)
This is good for cars that are running high compresion and there motors are prone to detinaion and they want less timing at lower rpms while under a high load and more at higher rpms to gain more horse power when detination is less likely to happen.

If a street motor is build with the correct compresion for pump gas,it will not need anything but the total timing set for the most power.
MOST PERFORMANCE MOTORS WANT ALL THE TIMING THEY CAN GET AND THE INITIAL TIMING IS NOT EVEN PART OF THE TUNE.:thumrigh:
Click to expand...

Sorry but I don't agree with the last part of that statement at all, unless you don't care at all how your engine idles. I said it earlier and I'll say it again. Initial timing plays a huge part in how an engine idles and it also has a direct reflection on street manners. A lazy timing curve will cost you drivability, torque, and fuel mileage. Your way of tuning reminds me of how I read 30 yrs. ago in a magazine to do it. I soon learned how much initial timing meant to a high perf engine and not to hook the vacuum advance up to full time vacuum, like the rags told you to do it.
 
to fishy68.
What i am saying is initial timing is not really a performance setting.
YES it will give you all the things you said \\ better mpg \\cleaner plugs\\
smoother idlle.UNDER LIGHT THROTTLE ONLY.
But i am a little confused by your statment that your motor will have spark knock with at anymore then 35 degrees total timing???
Yes i understand your motor suffers from spark knock at 35,but how is hooking up your vacume advance with 18 MORE DEGREES of timing going to take the spark knock away???
Your motor has too much cyilinder presure,thats why you can't go past 35 degrees total.
You said this happens when you run your motor with the distributer vacume advance system not hooked up.(less timing=more knock Please explain, you lost me there.)
I was saying that a motor properly tuned will not need anymore then the total timing set to run really good as far as drag performance goes.
THE WAY YOU HAVE YOUR CAR SET UP WILL BEAT MINE IN THE ECONOMY DEPARTMENT FOR SURE.I am trying to make a faster car and not a gas saver.:) I say that with no disrespect
The part i was saying about the vacume advance when not hooked up can affect your timing at high rpm's(over 5000 grand)is that it does move and is part of the distributers timing system and will affect your timing.
People that run high rpm motors will take the hole vacume canister right off the distributer and put a lock out rod in there.
GO TO MANCINIS SITE AND YOU WILL FIND THIS LOCK OUT DEVICE, EVEN FOR MSD DISRIBUTERS THAT HAVE A VACUME CANISTER.

Everyone knows when they time a stock distributer motor and rev it past 5000 you will see the timing marks start to shake and become not a single line anymore.This is because the stock distributers internal parts start to move and screw with your timing.
When you use a stock distributer ,for a performance DRAG CAR\STREET CAR ,the list of performance improvments go's like this:


1)CHANGE THE ADVANCED WEIGHT SPRINGS \\ JUST LIKE THE MOPAR THE PERFORMANCE DISTRIBUTER.
2)TAKE OFF THE VACUME ADVANCE CANISTER AND LOCK IT OUT.

3)LOCK OUT THE ADVANCE WEIGHTS

4)GET A MSD OR BETTER DISTRIBUTER CAUSE YOU DON'T NEED A FACTORY ONE ANYMORE.

I did not get my info from 30 years ago and i never even talked about what vacume port to hook a vacume advance up to for it to work correctly and yes the shop rags do talk to me and i have a name for each one.:-D

P.s.|||phisy68 waiting for your reply about how more timing helps you with your spark knock:-k
BUY THE WAY I LIKE YOUR CUDA \\IT'S COOL
Everyone has there own way of doing stuff and thats what makes it fun.
 
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