Anyone ever run this Purple shaft?

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gliderider06

gliderider06

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Have any of you tried this cam? I was thinking of getting it. Looks like a little more duration and lift than the .484 cam. I wonder if it would be worthwile to replace my current comp 280/.480 that is in the 360 now.
Advertised Duration 288/288
@0.050" 245/245-
centerline 108
Lift 497/.497
recommended springs P4120249

Camshaft packages for 273, 318, 340 and 360 pre-Magnum applications. Includes camshaft, tappets, assembly oil and instruction sheet.

P4529959
 
I've run plenty of 508 purple shafts. That one is VERY close. It'll be nasty.
 
I've run that exact cam with 2 different intake and carb combos.
Want is it you want out of it?

You do realize that is a oval track cam with a narrow power band and it's designed for the track, not for the street. MoPar says to run it installed at 106 IIRC. It has a nasty radical idle. When I ran it, people would drop out from there own challenge right at the line.
 
I did not know it was a circle track cam. The old Comp 280 magnum grind cam just is not what I was expecting. it runs out of steam at 5500 rpm and I was looking for a bit more power out of my 360. I thought it would have a bit more grunt than what the Dart has now when I built it. I was thinking of putting 1.6 rockers on it or changing the cam to a Voodoo grind. Just brain storming...
 
All info on your motor would help us help you.
 
Yes, its a 360 bored .040 9.5/1 comp. 2.02 J's, 3 angle valve job, port matched & surfaced .010. Comp 280/.480 magnum grind. Eddy RPM, 650 DP. MP Electronic dist converted to HEI. Headers, TTI duals with Magnaflow Mufflers.
I have close to 1000 miles on the rebuild. Runs really good, Just thought it would have more is all.
Its in a 68 Dart 4-speed with 3.23 suregrip 8-3/4 rear.
Thanks if I did not already say so
 
Before you change a bunch of stuff, that cam should pull harder than 5500.
Check you fuel pressure, put a gauge on it where you can read it all the way thru the run.
Does it run out of steam in 2nd gear, 3rd or all gears.
 
sireland67 said:
Before you change a bunch of stuff, that cam should pull harder than 5500.
Check you fuel pressure, put a gauge on it where you can read it all the way thru the run.
Does it run out of steam in 2nd gear, 3rd or all gears.
Click to expand...

Excellent question..........

I've been checking out a few with a little more int/ext split, but with the 3.23's, you can't really go much bigger on the intake side without losing a lot of low end and drivability. And that MP cam will definitely lose both.
 
It does it 1-2 shift, 2-3 shift and I have not gotten it that high in the rpm to the 3-4 shift. I start to get nervous at my speed and let out of it and slow down. It pulls hard and quick to the 5500 then will not rev any more, so I go to next gear. Makes me wonder and think it should go higher.
 
Sounds like you are running out of fuel or air.
What air cleaner are you running on it? Try a hard run with no air cleaner.
I still think it is running out of fuel, 650 DP should have plenty off pull if there is fuel.
 
I have a 14x4 open element air cleaner, 3/8 fuel sender and hard lines into a stock replacement pump. I have actually tried 3 different carbs and they all acted the same; this 650 has been the most street friendly.
Thanks!
 
If it completely noses over at 5500, it could be the valve springs are not quite up to snuff. Honestly though, I've put together several engines like yours, and they do tend to top out in the 5500/5700 range. I'd stay away from the cam your talking about at this point, unless you want to do a lot of racing. I understand going to the top of 3rd or 4th gear with your combo.....that's some serious mph :D.

Bottom line, the cam you have is a decent off the shelf grind, and some timing and carb tuning may help with how it feels.
 
I agree with OldmanRick 100%. Most likely valve spring itis, maybe fuel delivery. The Magnum 280 is a decent grind, and is typically out of steam around 5700ish in a warmed up 360. Yet you should still be able to rev it to 6000+.
 
That's about where the cam should nose over. 5500ish

Make sure the timing profile is right before tearing into it. It can make a huge difference in how the engine accelerates.
 
Yea it is a circle track cam, 1/4 mile flat track (flat turns)
For what I was using it for, it worked well. Here where I live (Long Island) it was useful on the hwy.'s. the island is wedged shape from the sea level south shore to the lightly billed north shore that gets to about 350 feet or so at max. Traffic/roadways are generally grid north to south. Hwy exit ramps are barely bank if at all.

Once your at speed in the power band running the course, it was excellent having great torque out of the roads bends and exits/entrances. It did t padticuly have a high rpm top end charge. Works well in a 4spd manual car. Frequent Gear changes needed to stay where you needed to be.
Easy 400+ HP out of this cam with iron heads. Great for road race short tracks.

I agree with Skrewz and the above mention on valve springs but also wonder if you degrees the cam in. The RPM ceiling seems a little bit low. Perhaps it is off a 2 degrees?
 
Rumble, Now that you mention it, I had installed the cam with a 2* advance key on the chain sprocket. It was all I could find when I built the motor. I forgot all about that... As far as the valve springs go, they are new and were set-up by the machine shop. He told me that they were a littly stiffer than what the cam card called for, but was good B/C I would not have to worry about valve float. If I recall it was somewhere around @20# stiffer at installed height +/- 5#.
Guess I should change cam key
 
I looked back and the springs I used are 995-16. They have a seat pressure of 115#, and open 335#. The cam I used calls for spring 901-16. A seat pressure of 101# and 245# open.
I really don't think that the springs are my issue, and might be the timing.
 
I did use a stock replacement module and just bought an MSD module to try out. Hopefully it helps.
 
Try to get a fuel pressure gauge on it in the car and see what it does. Springs should be ok but it should pull to 6000 I'd say with that cam. Stock fuel pump is what I noticed stuck out to me. 3/8 sender but is the hard line 3/8 too? Or stock 5/16? What about pump to carb line and filter? Most replacement pumps are just 1/4 NPT inlet/outlet. I'd check fuel pressure and make sure is good then go from there.
 
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