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Smitty 03-08-2005 07:04 PM

502 Mag MPI cam specs
 
1 Attachment(s)
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.

Pat McPherson 03-08-2005 07:32 PM

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

Gizmo 03-09-2005 11:08 AM

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.

cstraub 03-09-2005 12:00 PM

Re: 502 Mag MPI cam specs
 

Originally Posted by Pat McPherson
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

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

rmbuilder 03-10-2005 05:34 PM

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

Pat McPherson 03-10-2005 06:53 PM

Re: 502 Mag MPI cam specs
 

Originally Posted by cstraub
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

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:

cstraub 03-10-2005 07:29 PM

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

Smitty 03-10-2005 07:50 PM

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

Pat McPherson 03-10-2005 08:33 PM

Re: 502 Mag MPI cam specs
 

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

Chris

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

Pat McPherson 03-11-2005 07:24 AM

Re: 502 Mag MPI cam specs
 

Originally Posted by Bigwavz
Thanks Bob

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

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?


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