Mopar performance camshaft help aka purpleshaft
#970131
04/09/11 10:52 PM
04/09/11 10:52 PM
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Joined: Apr 2008
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California
court9155
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Couple of questions. Is this a purpleshaft cam? Pretty sure it is cuz it did sound aggressive in the car and it is PURPLE.....but you never know. Ive only seen one other purpleshaft cam and it was purple....but it was used. Ive never used one new out of the box. Also, is there a part number or something hidden on it???? Cant find anything but a few numbers by the distributor drive and they dont cross over to anything. Also one lobe has what appears to be casting flash on it....is this common on mopar cams, if this is a mopar cam? It is a one bolt cam so maybe its the lower end of their cams? Im just trying to see if this thing is useable in my 67 383. Very mild 383, with new rings/bearings and 30 over flat tops, along with a set of freshened up 516 heads..... Also are the pushrods supposed to be solid? No oiling hole in the middle??      Any help would be greatly appreciated. Also, I kept the lifters marked to their appropriate bore.
67 charger
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Re: Mopar performance camshaft help aka purpleshaft
[Re: court9155]
#970132
04/09/11 11:04 PM
04/09/11 11:04 PM
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Joined: Sep 2004
Posts: 2,091
oberlin, Ohio
Rapid340
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top fuel
Joined: Sep 2004
Posts: 2,091
oberlin, Ohio
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Looks like a purple cam. Measure lobe lift and it should be obvious which one it is. You could carefully grind that casting flaw off. The lobes I can see look really good. 
1971 Factory Appearing Duster 340 11.000 @ 122 mph
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Re: Mopar performance camshaft help aka purpleshaft
[Re: court9155]
#970134
04/09/11 11:28 PM
04/09/11 11:28 PM
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Joined: Jan 2007
Posts: 1,668
Mi,U.S.A.
mike s
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Mi,U.S.A.
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There is no part number on the cam.
There are several modern cams that will work better but if you want to use it,having a shop with a cam doctor check it is the best way to determine which mopar cam it is.You could measure the lobe lift yourself with a caliper.Measure the lobe to the highest point on the lobe.(top to bottom)Then measure the lobe at it's smallest part.(side to side)Subtract the smaller number from the larger one.This is the lobe lift.Multipy the number by 1.5 and it should be the lift at the valve.It will not be exact because the stock rockers will not be at the exact 1.5 ratio called for.Only problem is that there were several Mopar .484 lift cams with the same lift but much different duration.
It might be a 284/484 or 292/509 hyd Mopar cam and I would not recommend them for your app.Hope fully it is either the.455,.470 or.480 lift cam.Don't forget the matching springs.
There are no holes in the pushrods because BB mopars oil thru the block and head.Then thru the rocker shafts.
Leave the gun.......take the Cannoli's....Mike
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Re: Mopar performance camshaft help aka purpleshaft
[Re: court9155]
#970136
04/10/11 01:11 AM
04/10/11 01:11 AM
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Joined: Feb 2010
Posts: 18,493
Granite Bay CA
Kern Dog
Striving for excellence
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Striving for excellence
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Granite Bay CA
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Quote:
Thanks for the info on how the heads/rockers are oiled. I was not aware of this, however, why is there a bleed hole in the rocker arms at the pushrod cup??
Dan
The small hole on the pushrod cup is for oiling the top of the pushrod.
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Re: Mopar performance camshaft help aka purpleshaft
[Re: court9155]
#970138
04/10/11 02:03 AM
04/10/11 02:03 AM
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Joined: Apr 2008
Posts: 301
California
court9155
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Mic'd both lobes and im getting .4695 lift if I factor in the 1.5 rocker......
No purpleshafts match that.....
Done it several times with the same results...are they possibly ground off a little? Like maybe this is a 474 cam with a little wear?
Dan
Last edited by court9155; 05/12/11 05:54 PM.
67 charger
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Re: Mopar performance camshaft help aka purpleshaft
[Re: Kern Dog]
#970140
04/10/11 02:20 AM
04/10/11 02:20 AM
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California
court9155
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Quote:
The closest could be the 474 that you mention. Thats a decent cam. I had one in a reringed 440. It will lope a little more in a 383.
If you are getting consistant numbers from measuring the lobes, you are okay. It is highly unlikely that if the cam lobes started to wear, that they would all wear out at the same rate. Look at the lifters. The bases should look smoothe and nearly flat. Any sign of scuffs or scratches could be trouble.
lobes and lifters actually look pretty good. I measured them all and it took forever. Got from .4678 to .4707 with the 1.5 rocker factor so Imma call it .474.
I mic'd a ford motorsport racing cam hydraulic roller that is spec'd at .512 lift and is brand new in the box. I got from .5037 to .5118 with the 1.6 rocker factor
Last edited by court9155; 05/12/11 05:55 PM.
67 charger
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Re: Mopar performance camshaft help aka purpleshaft
[Re: Kern Dog]
#970142
04/10/11 03:17 AM
04/10/11 03:17 AM
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California
court9155
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Quote:
Quote:
Imma call it .474 cam.
I mic'd a ford motorsport racing cam hydraulic roller that is spec'd at .512 lift and is brand new in the box. I got from .5037 to .5118
WE machine the crankshafts to a set spec. We machine the rods too. WE assemble the motor while checking bearing clearances, being careful to torque to specs. WE do all that we are supposed to do, then some company ships a cam with irregular lobes. How the heck are we to do any better?
I'll bet that hardcore racers and NASCAR teams demand perfection in this area. When the stakes are that high, the few thousandths of variance in cam lobes can mean a few thousandths in a race. Thats all it takes to be in second place.
Yea thats what I get for using OTS cams...not on good cam cores to begin with.
Should go with cam motion, jay allen etc but when it comes to the old mope I just wanna get it mobile...
Last edited by not_a_charger; 04/11/11 08:33 AM.
67 charger
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Re: Mopar performance camshaft help aka purpleshaft
[Re: court9155]
#970144
04/10/11 12:49 PM
04/10/11 12:49 PM
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Joined: Jan 2003
Posts: 1,263
Southwestern Ontario Canada
racealittle
pro stock
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Southwestern Ontario Canada
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The MP .474 280 is a great cam for a driver that sees a little bracket racing action.
Too many cars, too many parts, too little coin, too little space to work in, too little time left to make it all happen!
Update: down to one ride, still too many parts, a little more jingle in the pocket, gaining space, and it's going to happen this year!
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Re: Mopar performance camshaft help aka purpleshaft
[Re: NachoRT74]
#970147
04/10/11 02:53 PM
04/10/11 02:53 PM
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Joined: Apr 2008
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California
court9155
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i can tell you that this cam worked very very well in my late uncles 68 383 formula s fastback.
On 100 shot it went 11.11s on 9 inch k mart slicks in about 1985 through exhaust manifolds.
Anyway Ill also measure the lift at the valve after I install it.
I must be doin something right when I measure the base circle because I have done this to a few cams and am very very close.
67 charger
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Re: Mopar performance camshaft help aka purpleshaft
[Re: court9155]
#970148
05/12/11 09:54 PM
05/12/11 09:54 PM
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California
court9155
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Well, for anyone thats curious or doin an internet search like I did, measuring a camshaft for lift (not ready to tackle the duration deal yet but will do that too) with the cam out of an engine will prove very difficult. I was close, but not close enough.
I measured it out of the engine and came up with .474 once I figured in the 1.5 rocker ratio factor.
Well today just to make TRIPLE sure what LIFT I had on this cam I installed it along with my timing set, into my 383 shortblock. I then took one of the lifters (both cam and lifter approx 10K miles on them wear pattern looks great, fyi) and set my dial indicator up to be on the top ridge of the lifter, not the plunger (just so I dont have any preload drama to factor into the equation) and measured it. Came up with .323 actual lobe lift the intake lobe.
That is .4845
Im callin this the .484 lift mopar cam.
This is the way to do it.
Did the same thing on a small block ford with an f cam in it today as well, same deal.
Then did my custom ed curtis FTI cam in another small block ford, same deal.
Now Imma tackle figuring out the valve events and duration with my timing set and degree wheel and dial gauge!
Dan
67 charger
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