Wut'n'ell is the intake centerline on a P4120231

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67Dart273

67Dart273

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Summit shows lobe separation at 108, but I can't find a cam card, or a verifiable listing of timing events

Found this: in an old thread but am not sure it's accurate

http://victorylibrary.com/mopar/mpcam-tech-c.htm

284° Hydraulic: P4120231

Intake Duration, Nominal

284°

Exhaust Duration, Nominal

284°

Intake Duration @ .050”

241°

Exhaust Duration @ .050”

241°

Intake Lobe Centerline

108° ATDC

Exhaust Lobe Centerline

108° BTDC

Lobe Separation Angle

108°

Overlap

68°

Intake Opens

34° BTDC

Exhaust Opens

70° BBDC

Intake Closes

70° ABDC

Exhaust Closes

34° ATDC

Intake Lift

.484"

Exhaust Lift

.484"
 
Straight up (108 )

Edit: confirmed specs on a few different websites. sounds legit.
 
Depends on the combo. Without any real info and that cam lobe 104-106ICL is a starting point. MP recommends 106 ICL
 
goldmember said:
Depends on the combo. Without any real info and that cam lobe 104-106ICL is a starting point. MP recommends 106 ICL
Click to expand...

Where does it say MP recommends 106? everything i'm reading says 108 and the valve events are consistent with 108
 
OK I guess what I'm asking is HOW do you know that? Where "at MP" do you find this info?

Between the two of you guys we already have 104 -- 108
 
frosty_the_punk said:
http://www.monicattichrysler.com/comersus/store/comersus_viewItem.asp?idProduct=255#

http://www.summitracing.com/parts/dcc-4120231

http://flag.blackened.net/mopar/camchart.html

http://www.chicagoconnection.us/index.php?main_page=product_info&products_id=944

https://www.yearone.com/Product/1966-74-A-B-E-Body/P4120231

Shall I keep looking?
Click to expand...

THANK you. Here's the deal

I had found this link you posted:

(as an example................)

http://flag.blackened.net/mopar/camchart.html

ANYbody can post up a website with some chart they got somewhere. That is not a Mopar source.

Maybe I missed it, but nowhere on the Summit specs do I find a recommended ICL, even a starting place

These guys look a little trustworthy

http://www.monicattichrysler.com/comersus/store/comersus_viewItem.asp?idProduct=255#

About 90% of the rest of the hits I got were just like here --bantering on a board.

I don't understand why there doesn't seem to be an original Mopar source for this........................

Just trnna make sure the info we START from is correct. I make enough mistakes "on my own."
 
Del,

Install it at 104. Heavy truck maybe even 102 if Valve to piston clearance is OK.

As far as me, I've NEVER installed an MP cam on the LSA cut for the ICL. They always go in at least 4 advanced and sometimes as much as 10 (odd situation).
 
You're right, the summit site doesn't say anything about the installed ICL.

Truth be told, the difference between 106 and 108 ICL is probably not very much and would be difficult to notice.
 
For 241 at .050 and an installed 104 CL, shoot for .050 tappet lift

Intake open 16.5 btdc
Intake close 44.5 abdc

Exh open 44.5 bbdc
Exh close 16.5 atdc
 
Thanks, you guys, THANKS!!. We are planning on looking at this Monday. "Mine road trip," LOL
 
im looking forward to this work out day, its going to be a learning section that ive never been taught, thanks again DEL and Crackedback the 2 of you seem straight up from our conversations so far!!!!!!!
 
Thanks you guys for your help

Well guys "we" had a great but tiring day (I just don' have the suds anymore) out at Mudog's place. we checked the cam on the existing drive at 110--111 CL if I remember right, and "tried" the new set at 6*. Came in about 105, which is where we left it.

He has a Mopar dist. which looks like the old Mopar dist, but still has the adjustable advance, as well as a new style Jegs "Mopar replacement" which is different. They don't give you a key for the advance plate, so "I just guessed" and cranked the slots a little shorter. Hopefully they won't be TOO short.

Wasn't running when I left earlier, I was beat. Scribed the balancer for him and checked timing marks, were right on the money
 
Oh dang, I have the * key thickness and use drill bit shanks to set mechanical in those distributors.

It should run a bunch better
 
Wish to 'ell I'd thought of that...................You have a chart you can post the dimensions?
 
The old MP small block book says 106 installed centerline. I prefer to install them 4*-6* advanced. I profiled the lobes on that same cam a couple of years ago. The Mopar specs are way off what the cam actually is.

true advertised duration @ .006
294*.....MP claims 284*
true duration @ .050
238*.....MP claims 241*
true duration @ .200
143*.....MP no specs

Pretty primitive grind by today's standards.
 
67Dart273 said:
Wish to 'ell I'd thought of that...................You have a chart you can post the dimensions?
Click to expand...


This is what I have. I did read somewhere that the 16 was really 14, 18 really 16.

12 0.125
14 0.140
16 0.155
18 0.170
20 0.185
22 0.205

Take it for what it's worth and always verify!
 
crackedback said:
Del,

Install it at 104. Heavy truck maybe even 102 if Valve to piston clearance is OK.

As far as me, I've NEVER installed an MP cam on the LSA cut for the ICL. They always go in at least 4 advanced and sometimes as much as 10 (odd situation).
Click to expand...

Right on! I've ran this cam in a number of different combos and Have always installed it at 104. About 20 years ago we were at the Gator Nationals and we wound up by accident camping next to the Mopar group that ran the display trailer at the track. I made friends with a Mopar tech ( don't remember his name now) But knew his Mopar ****. Told him what I was building a 70 340 4sd Duster with this cam 284/484. He advised installing it @ 104. Worked out great.
 
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