Purple Cam Design Question

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moper said:
From what I know, a few of the MP cams were altered in the 90s. The lobes were not.
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It's in the MP engine book. They were redesigned to take advantage of the large Mopar lifter diameter. That's what the book says. They don't get specific.

It's something that can be debated until the end of time. Are the MP cams the best out there? Some will say no. Some will say yes. I say just like ANY OTHER camshaft, it depends on what you are doing.

They used to be the best you could get for a Mopar......and for a lotta years. A lotta races were won with them. Records have been broken with them. A lotta money has been won with them.

Would "I" choose one today? Probably not, unless I already had one on the shelf. And it would need to be an OLD RUN, because of their quality control. Quality control however, would be the only reason I would not include them on my short list.

I build a lot of engines with stock, as cast heads. That's what the MP cams were designed for. If the quality control was there, you can bet I would use them, regardless of what anyone else might say.
 
was it t67power, rumblefish?
there was a post about Herb McCandless and his findings and something about an article - victory tech or something
 
I always thought hydraulic purple shafts were designed to get the most out of basically stock heads and rockers.
 
Cam manufacturer choice is mind boggling for me. i just stick with the Mopar stuff. You can do a post on the internet on any of there cams and find nothing but good things were people are happy with their grinds.
I have so tried to change but to what??? Hughes, Comp, Diamond, Racer brown , Isky , crowther,,,,ect Then all the specs seem to be a little different from manufacturer to manufacturer???
Then you have Roller- hyd or mech . You find people that say rollers fall apart on the street, The 440 doesnt have adequate oiling for any kind of idle situation. Hyd rollers float, mechanical's have to high a spring pressure for street
Mopar Muscle is always using rollers in there street builds but if you search you'll find people with roller assemblies that came apart and totalled there engine because of the pieces floating around.(alot of people say you need oil modifications to the heads of an RB and the same number say you don't)
i have used 8 purple sticks to date and never had a flat lobe but Im not an all out racer either and not the brightest with motors as of yet?
 
tooslow said:
Cam manufacturer choice is mind boggling for me. i just stick with the Mopar stuff. You can do a post on the internet on any of there cams and find nothing but good things were people are happy with their grinds.
I have so tried to change but to what??? Hughes, Comp, Diamond, Racer brown , Isky , crowther,,,,ect Then all the specs seem to be a little different from manufacturer to manufacturer???
Then you have Roller- hyd or mech . You find people that say rollers fall apart on the street, The 440 doesnt have adequate oiling for any kind of idle situation. Hyd rollers float, mechanical's have to high a spring pressure for street
Mopar Muscle is always using rollers in there street builds but if you search you'll find people with roller assemblies that came apart and totalled there engine because of the pieces floating around.(alot of people say you need oil modifications to the heads of an RB and the same number say you don't)
i have used 8 purple sticks to date and never had a flat lobe but Im not an all out racer either and not the brightest with motors as of yet?
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You can run a solid roller with great sucess in a bb or sb mopar. Just use a rev kit.
 
On the street were you have to idlle? Whats a rev kit? What Cam manufacturer do you reccommend???
 
tooslow - Stick with the solid flat tappet deal, consult the cam manufacturer for proper spring and break in procedures, run a good high zddp oil like Joe Gibbs, Brad Penn, or the Not Legal for Street Use VR-1, and you'll be fine.
The MP .528 is a nice small cam. If you want more pep with the new heads, I'd go with something like the XS282S or the Magnum 294S both from Comp.
 
Here's the main reason "I" like the Mopar way. Nobody, and I mean NOBODY else in the industry ever came up with such a comprehensive "recipie list" as in the Mopar Performance books.

I mean, you pick the parts they say to pick and boom, you're in whatever bracket you choose on the strip. Those camshafts were an integral part of those recepies. Wanna 12 second car? It's in the book. Wanna 9.90 index race car? It's in the book.

Sure, you can substitute this and that, BUT, with those recipies, the work is already done. NO guess work, no bench racin on a forum askin what cam is better this or that. Just open the book up, pick your recipie and go.

Sure, there are more popular grinds with faster rates, blah blah blah, but if the Mopar cams will get the car to run the same speed, what's the difference? My only concern as said before now is the quality control thing. So.....that said, what I'd probably do now is follow the recipie I wanted and sub the closest thing to the recommended Mopar cam that I could find.

Last thing I'll say on it is this.....why do you think Comp has come out with those Purple cam copies? Because they work, that's why.
 
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Here's the main reason "I" like the Mopar way. Nobody, and I mean NOBODY else in the industry ever came up with such a comprehensive "recipie list" as in the Mopar Performance books.

Your right . I am not a motor Gur!u its hard to dechiper among all the choices out there but the Bible i have and with that I am good--I forgot all about my Mopar Performance booK=thanks
Just follow the recipe
 
LOL, they allways worked for me. Looking foward to trying out the 11 sec. list.
 
StrokerScamp said:
Last thing I'll say on it is this.....why do you think Comp has come out with those Purple cam copies? Because they work, that's why.
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I think you make a wrong assumption there. Comp made them because of the popularity of those recipes, definately. But it was the desire to get a bigger share of the market, not to duplicate them. If you take the time to compare the lobes Comp uses, you'll note two things:
-The general shape is that of their "nostalgia" lineup, which is not based on ability of different lifter diameters, and is, according to the lobe catalog, designed to have decent power and that "choppy" idle.
- Comp has different exh lobes for each camshaft. They are VERY different cams, they just carry the "284/484" or "292/.509" labels. Kinda like a modern 5.7L "Hemi".
The conclusion I have to arrive at is the main push for them is just marketing. Not quality of original design. The design was changed by Comp because it was only good at making horsepower in the MP form. It wasn't (and still isn't comparatively speaking), good at idling, making power, running power brakes, and producing huge torque figures all at once. In short, they are race cams from an older age. Modern cams are more well rounded, and in terms of overall power, and when applied similarly to the MP idea of "make max power" modern technology makes more power overall. You can think of it this way too.. Direct Connection had to use mushroom tappets to get high rates of lift. Comp, Lunati, Bullet, and others do it on the std .904 lobe. It's because technology has progressed to allow for it. Not because the mushroom didnt work.
 
moper, can't argue with any of that. All good points.
 
rumblefish360 said:
LOL, they allways worked for me. Looking foward to trying out the 11 sec. list.
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Lately i have been trying to get fancy but I have I have always followed the book just seemed a little outdated as of late and I 've been trying to be 2011?
FOLLOW THE RECIPE AND ITS LIKE BAKIN A CAKE
i might even dig out my Tunnel Ram-(I like-em)
 
moper said:
I think you make a wrong assumption there. Comp made them because of the popularity of those recipes, definately. But it was the desire to get a bigger share of the market, not to duplicate them. If you take the time to compare the lobes Comp uses, you'll note two things:
-The general shape is that of their "nostalgia" lineup, which is not based on ability of different lifter diameters, and is, according to the lobe catalog, designed to have decent power and that "choppy" idle.
- Comp has different exh lobes for each camshaft. They are VERY different cams, they just carry the "284/484" or "292/.509" labels. Kinda like a modern 5.7L "Hemi".
The conclusion I have to arrive at is the main push for them is just marketing. Not quality of original design. The design was changed by Comp because it was only good at making horsepower in the MP form. It wasn't (and still isn't comparatively speaking), good at idling, making power, running power brakes, and producing huge torque figures all at once. In short, they are race cams from an older age. Modern cams are more well rounded, and in terms of overall power, and when applied similarly to the MP idea of "make max power" modern technology makes more power overall. You can think of it this way too.. Direct Connection had to use mushroom tappets to get high rates of lift. Comp, Lunati, Bullet, and others do it on the std .904 lobe. It's because technology has progressed to allow for it. Not because the mushroom didnt work.
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thanks for that moper was wondering what happened to those mushroom cams had one in a 440 long ago it was radical but man did it pull hard.....
 
tooslow said:
On the street were you have to idlle? Whats a rev kit? What Cam manufacturer do you reccommend???
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Rev kit's are designed to keep the roller lifter in full contact with the cam. Roller lifters can skid on start up,creating flat spots,and eventually failure.

http://www.iskycams.com/pdfcatalog/2004-05/page21.pdf

The rev kit also reduces the spring load at the valve.

I like mopar cam's. I've run some in my small block's and was always happy with em. Radical idle yes. BUT...mopar hasnt designed a NEW cam in years,so the old grinds have been outdated by new research. I would go with a company like comp or lunati,as they are on top of mopar .904 lifter design and build thier cams around the .904 lifter,not some chev junk.
 
just got my 360 back in and running
i'am using the 292/509 mopar cam and trust me i looked for a updated cam that would make more power and could not find one i liked
if anyone has any suggestions i would like to here them


engine specs
360
kb190s stock crank and rods
340x heads with alittle work
and a windage tray
car 74 dart sport (3450 with me in it)
727 manual valve body
4.10 gear and 3500 convertor
ran a best of 12.58 108 mph street car i think it runs real good
 
bad440 said:
when you go to the link, to the 590 cam, why does it say incorrect @104 and why would it be?
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I wouldn't trust that site 100%. That guy is known in the early Hemi circles for misinformation. I believe the 104* overlap is correct.
 
there are cams that do a little better at this and have better vacuum and low end butt the purple cams where developed on mopar la,s and big blocks and are great old grinds and when matched with the right parts are hard to beat.
 
moper said:
The difference is the old grinds can make power in a fairly narrow way. You lose low end and vacuum to get horsepower. In the same identical engine, a modern cam will make the same or more horsepower, but you also get things like idle quality, no less loss of low end, and longer flatter power peaks throughout the range. MP cams also are made terribly. The QC is as good as the low bidder can get them. So overall, they work but not as well. I'll spend to get what I need for results, and the base parts mean nothing. If the cam's matched well to the parts, any cam will make power if it's made right.
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This is true! the MP grinds are far from a .904" lifter grind,if you have adcole equipment you will see this. That said they CAN work well but I haven't used them in many years. For camshafts you really should save the effort and call Tim @ Bullet cams since I don't give info from the net at this time. I did a cam last month the picked up .2 and 2mph over a shelf grind(on a customers truck) and the ignition timing was several degrees from optimum. My suggestion is don't worry about "aggressive" lobes and find something that fits the combo,too many focus on the numbers listed @.050 or elsewhere,and they mean nothing. I'm sorry if that rubs some wrong,but it's a fact.
 
o1heavy said:
just got my 360 back in and running
i'am using the 292/509 mopar cam and trust me i looked for a updated cam that would make more power and could not find one i liked
if anyone has any suggestions i would like to here them


engine specs
360
kb190s stock crank and rods
340x heads with alittle work
and a windage tray
car 74 dart sport (3450 with me in it)
727 manual valve body
4.10 gear and 3500 convertor
ran a best of 12.58 108 mph street car i think it runs real good
Click to expand...

I'd guess you should be running 11.70's or better.Your combo would be easy to pick up but much of it will depend on the heads and tune up. PM me if you want a custom grind.
 
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