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Purple Stripe cam I.D.

biomedtechguy

biomedtechguy

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I believe it is a 292° .509" cam. Sounds like it, pulls like it, and I'm not the only one who thinks so.
In my 440
I know it's still a guess.
How could I "measure" to see what it is? I'm guessing that if the lift was .509, that would be enough to tell?
The only cast number I can find in it is this:
1103
20150829_141858.jpg
 
I believe you could pull the valve cover and but a dial indicator on the valve or rocker and get the measurement. Never did it that way but I read something like that recently, I believe @wyrmrider posted about it.
 
1967coronet440 said:
I believe you could pull the valve cover and but a dial indicator on the valve or rocker and get the measurement. Never did it that way but I read something like that recently, I believe @wyrmrider posted about it.
Click to expand...
Thanks, I will do a search for wyrmrider posts and/or PM him.
Anyone else comment?
 
You could always post a video of it running?
Some of these guys can tell just from the sound.
 
moparedtn said:
You could always post a video of it running?
Some of these guys can tell just from the sound.
Click to expand...
That is what happened that brought a number of factors together and "convinced" me it is a 292/509. I have found that it pulls strong to 6k easily since I replaced the valve springs, but other than the cam, 6 bbl, and headers there's no real explanation. So I figured the cam is the 292 vs the 284.
I started it up with open headers at Mopars at the Marina and a guy came up and said "509" and he is the one who made me "sure" between the way it runs and what he said that it is the 509 cam.
Listen:
 
Yep. By comparison, here is another 509 Purpleshaft:



...and my own (faster idle):
 
Sound is sound. Cam design is cam design. The two ain't the same. The pic shows a casting number, not a grind #. As I recall the grind numbers are on either end of the cam.
 
66Satellite47 said:
Sound is sound. Cam design is cam design. The two ain't the same. The pic shows a casting number, not a grind #. As I recall the grind numbers are on either end of the cam.
Click to expand...
Thanks! I am just guessing until I take a lift measurement (I assume would be the best option). I will do that when I install the TrickFlow 240s (if I live long enough)
 
The best way to figure what you've got is to use the dial indicator & degree wheel to measure both the total lift & the duration at whatever lifter rise (@.050, .020, or?). I presume the purple shafts are still the stuff from the '70's (old technology). But don't get me wrong, I'd put a couple of my '70's cams against the modern stuff performance wise, the old tech drawback is valvetrain stability & durability IMO. Cam selection is a really tough thing, especially if it's not a single purpose vehicle.
 
I don't believe MP cams have any stamped or cast numbers that ID them.
 
Lift by itself won’t tell you what it is. There are 2 Mopar .509 292 cams. One is 108 degree centerline and the other is 112.
 
66Satellite47 said:
The best way to figure what you've got is to use the dial indicator & degree wheel to measure both the total lift & the duration at whatever lifter rise (@.050, .020, or?). I presume the purple shafts are still the stuff from the '70's (old technology). But don't get me wrong, I'd put a couple of my '70's cams against the modern stuff performance wise, the old tech drawback is valvetrain stability & durability IMO. Cam selection is a really tough thing, especially if it's not a single purpose vehicle.
Click to expand...
condor74 said:
Lift by itself won’t tell you what it is. There are 2 Mopar .509 292 cams. One is 108 degree centerline and the other is 112.
Click to expand...
I will be satisfied to measure the LIFT. If the lift is appx .509, I know for a fact that it's a 292° .509.
That will tell me enough.
I have already got the details from :lowdown:IQ52, my friend, in order to get the few key parts to make the TrickFlow 240s work with my current cam, Comp Cams springs, and Comp Cams lifters.
If the cam is what I think it is, the 240s will really wake up my 440.
On that note, will these (presumably stock) pistons with valve reliefs AND the 78cc heart shaped combustion chambers work as far as compression ratio goes. In other words, what will the change from stock 452 1978 heads to the 78cc heads do to my compression ratio and appx what will it wind up at? 1971 440 had a 9.25:1 CR IIRC.
Thanks.
Here's the pic
Engine piston tops.jpeg
 
Last edited:
I'm sure you are correct that a modern performance head will be a substantial increase in power compared to 452's, especially if the 452's aren't ported. If the 452's aren't milled much they'll be around 88cc. Keep in mind the true CR is the sum of many volumes, it must be actually measured and calculated. The aluminum heads want more CR by nature. A simple check with the dial indicator will tell you the lift.
 
So if my current CR is 9.25 :1 w/88 cc heads, what would 78 cc heads raise it to?
 
How do you know it's 9.25? The factors are: bore/stroke, deck height, net valve notch/dome vol, head gskt thickness/bore, chamber vol. Just a rough guess based on some estimated numbers gives me a .9 to 1.0 increase in CR going from 88cc to 78cc. All the factors I mention are variables. You need to know what each is to do the math.
 
do a compression check before and after each change
If you take of the timing cover check your chain and you might see markings on the front of the cam, check the chain
see if you have adj rockers and solid lifters- most likely you would have caught this some time
did you buy the purple shaft or did it come in the motor? it might be a regrind so check now instead of later
turn the motor over slowly and see if the rockers are going down relative to the valve (retainer) the same amount as up
the (uncorrected) rocker motion on a regrind (reduced base circle is different than stock which is slightly different than a higher lift cam
take each lifter out and inspect and put back in same lifter bore lifter crown should be convex- any that are not carefully inspect the cam lobe
stock rockers- any changes planned?
clearance your new heads for 3/8 pushrods
if you have to buy pushrods change out the lifters to Magnum/ AMC style and go 3/8 if all you have to do is clearance the heads- if you have to clearance the block wait till you do the shortblock
when you have the heads off check the deck clerance at all four corner holes and write it down for future reference- just use a dial caliber for close enough
get an adjustable pushrod for the rockers/lifters you are going to use and do the mid-lift drill b4 ordering pushrods
stock rockers can work just fine with a .500 lift cam
which of the two cams you have makes little difference if you like the way it drives
 
The cam came in the 71 440 in my 70 V-code Roadrunner
I already changed the following when a lifter collapsed about 3 years ago: pushrods (stock Mancini 440) CompCams supplied the lifters springs locks (10°) and retainers.
My future heads are going to be TrickFlow 240s.
See this thread/these posts for the details on the CompCams parts and plans regarding keeping the cam with the TF 240s until I can afford a stroker build:
https://www.forbbodiesonly.com/mopa...n-about-spring-options.150940/#post-910948714
and
https://www.forbbodiesonly.com/mopa...n-about-spring-options.150940/#post-910948766
 
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