502 Mag MPI cam specs
 

Does anybody know what the cam specs are for a stock 502 Mag MPI cam . It is a 2000 Gen 6 and I believe it is also a roller cam. I am asking because I need to buy Valve springs and retainers for the Edelbrock heads I am installing on this motor. I am keeping the cam stock for now. In case you are wondering why, can you say "Whipplecharged" :D :D

Below is a pic of one of my motors.

Re: 502 Mag MPI cam specs
 

From the GM Performance parts catalog:
Gen VI 454&502 HO
valve spring kit #12495514
valve spring cap and seal kit #12360872
valve stem key #3947880
I just bought the stuff for my rebuild...
About $150...
Good Luck

Re: 502 Mag MPI cam specs
 

BW - I have the specs in a book at home. I'm at work right now. If you haven't had a reply by time I get home, I will look them up and post.

Re: 502 Mag MPI cam specs
 

Pat,
Are you running hyd flat tappet or hyd roller. If you are running a roller you better re-think that spring choice. Sure those are fine for a car that the engine is going to see 2000 to 2800 rpm all day long driving with a few 5500 rpm shifts but they will not last in a marine application. You need to shoot for a minimum of 130# seat pressure at installed height.

Chris

Re: 502 Mag MPI cam specs
 

Bigwavz,

Cam specs for 502 MPI:
288*/288* seat
224*/224* @.050"
.483"/.483" valve
115.5* LSA
109* ICL
122* ECL

The spring kit Pat mentioned is:
1.487"
110# @ 1.88" installed
261 # nose
316# rate
Bob

Re: 502 Mag MPI cam specs
 

Well Chris,
Those are the springs that came in the engine stock.
The stock cam is going back in my engine so I don't know why a new set of stock springs wouldn't work?
The last set lasted 480+hours... :cool:
The stock roller cam is vary mild... :drink:

Re: 502 Mag MPI cam specs
 

Pat,
I wouldn't be that lucky. How much shim did they take after the seat were ground?

Chris

Re: 502 Mag MPI cam specs
 

Thanks Bob

It appears to be a smaller cam than I figured on. I might have to go a little bigger :D :D

Re: 502 Mag MPI cam specs
 

Chris,
There is a shim/washer under the springs, but I don't know how thick...

Re: 502 Mag MPI cam specs
 

I know this question has been asked before, but I'm going to ask anyway.
So what cam is the logical upgrade for a 454 or 502 MPI roller cam engine?

Personally my budget would not alow for all of the after-market goodies required for larger cam. Not to mention the ECM calibration issue.
Bob (rmbuilder) is there a little larger cam that could be used with the stock GM stuff and would not require ECM recalibration?

Re: 502 Mag MPI cam specs
 

I have a new in the box Crane 721 cam that is collecting dust on my shelf that I can make somebody an excellent deal on. Should be good for an upgrade.

SPECS: #139721

Valve Setting: Intake .000 Exhaust .000 HOT

Lift: Intake @Cam 325 @Valve 553 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 339 @Valve 576
Rocker Arm Ratio 1.70

Cam Timing: TAPPET @.004
Lift: Opens Closes ADV Duration
Intake 29.0 BTDC 67.0 ABDC 276.0 °
Exhaust 73.0 BBDC 31.0 ATDC 284.0 °

Spring Requirements: Triple Dual Outer Inner
Part Number 99896
Loads Closed 132 LBS @ 1.906 or 1 29/32
Open 395 LBS @ 1.346
Recommended RPM range with matching components
Minimum RPM 2000
Maximum RPM 5500
Valve Float 6500

Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 2.0 BTDC 32.0 ABDC 105 214.0 °
Exhaust 46.0 BBDC (4.0) BTDC 115 222.0 °







May not be much different but may still help somebody that needs a replacement.