Purple Shaft cam IDing

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pittsburghracer

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i have two newish purple shaft small block cams without cards. I installed these in an old engine to plot out lift numbers off number one intake valves. One cam out at 474 so that is pretty easy but one plotted out around .523 lift. Hmmmm. I guess the question here is can you easily identify a solid lift cam from a hydraulic cam?
 
There was a purpleshaft hydraulic cam that was bigger than the .509, I had one, but I can't remember what the specs were on it.
 
I got to positively I’d them so I can list them for sale. I might have to throw them back in a block for further testing. Thanks guys.
 
I got to positively I’d them so I can list them for sale. I might have to throw them back in a block for further testing. Thanks guys.
I bet if you put "Purple shaft" in the search box there will be dozens of threads but no answer. I don't think anyone knows and the cams didn't have any identifying stamps or marks on the end.
 
Don't the purple shafts have numbers on the front or rear?
 
Direct Connection # was P3412016 - for a small block......Cam # was ST21-108

Duration - 28x?? my data sheet has a bad spot on the third digit, sorry
Lift - 0.520" (at the valve)
Centerline - 110*
Lash intake - .018"
Lash exhaust - .022"
Recommended spring - P3412068

This one appears to be the closest to matching your 0.523" lift spec you stated. Easy to have 0.003" discrepancy due to measurement error and/or manufacturing tolerances.

Hope this helps you ID it.
 
Don't the purple shafts have numbers on the front or rear?



Some of them have a paint mark on them that at one time I believe helped identify them. But if so I haven’t been able to locate that info and probably most of the guys from back then are either out of the sport or long gone.
 
I bet if you put "Purple shaft" in the search box there will be dozens of threads but no answer. I don't think anyone knows and the cams didn't have any identifying stamps or marks on the end.



I have a lot of the old purple shaft cams saved on my computer which is now dead. A lot of the specs are there but little iding info.
 
Don't the purple shafts have numbers on the front or rear?
Yes and No, they were contract cams. The numbers you see are manufacturer contract numbers (IIRC) that didn't jive with any MP part number. Whom ever came in with lowest bid made the run they needed. Usually you can ID them with the lift alone. hydro cams have no lash ramp, they just pop the valve open because they run with no lash. Solids need some ramp to close their lash so youll see a slower ramp up. you can see this when you turn the cam under a dial indicator. Hydros will pop right up with little ramp, solids will gradually sneak up a longer ramp and then pop the lifter up.
 
Is there a COMPLETE list of all the purple cams anywhere anymore? There were a lot of numbers including all of the oval track stuff. I would think that cam is one of three or four. Either the .533 hydraulic with some wear, the .528 solid with some wear......who knows? I haven't the faintest idea how to figure hydraulic or solid other than a complete mapping with a degree wheel to see what the ramps look like, OR send it out for mapping. IF I was going to do the latter, there's only one place I would send it. I would send it to Jim at Racer Brown. He could map them and tell you for sure.
 
Is there a COMPLETE list of all the purple cams anywhere anymore? There were a lot of numbers including all of the oval track stuff. I would think that cam is one of three or four. Either the .533 hydraulic with some wear, the .528 solid with some wear......who knows? I haven't the faintest idea how to figure hydraulic or solid other than a complete mapping with a degree wheel to see what the ramps look like, OR send it out for mapping. IF I was going to do the latter, there's only one place I would send it. I would send it to Jim at Racer Brown. He could map them and tell you for sure.


Pretty sure one is brand new and was was in an engine but never started. Thanks for the info.
 
If you are near a cam grinder (GS comes to mind) and willing to spend a few $ then they can measure the cam and print out the specs and timing events.

It sucks that Mopar sucks at numbering their cams, blocks, ...
 
There was. But it was discontinued a long time ago. And when it got the axe, Chrysler called all the cams back in and sent them to the scrap yard, just like they always do.

The biggest hydraulic was the .533/320. That was a rowdy hydraulic grind.
 
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