7.4L cam

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07-12-2006 | 01:52 PM

MadMat

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7.4L cam

Can anyone confirm what the stock cam specs for a 1988 7.4L should be. My service manual states 350/352 advertised and doesn't state LSA - but this seems crazy so I'm sure it must be a misprint.
Thanks
Matt

07-12-2006 | 02:32 PM

OLDRAT

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From: GRAND LAKE, OK

Re: 7.4L cam

Mad,

The data I have for a 1988 7.4 (330 hp - not Mag) is:

Lift int-.461 and ex-.479 Advertised dur int-.350 and ex- .352.

Duration at .050 is 214/218 degrees, the lobe separation is
115 degrees

Merc PN 437-4734

OR

07-12-2006 | 02:46 PM

rmbuilder

MarineKinetics

Joined: Oct 2002

Posts: 942

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From: Rochester, NY

Re: 7.4L cam

Quote:

Originally Posted by MadMat

Matt,
You are correct, that is a mis-print in the manual. (Not the only one)
The correct spec are:
Merc #431-4734
GM# 3904359
278º/289º @ .006"
213º (214º)/ 217º (218º) @ .050"
.270"/.282" Lobe
.460"/.480" Valve
110º ICL
118º ECL
114º LSA
Bob

07-12-2006 | 03:00 PM

MadMat

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Re: 7.4L cam

Thanks guys.

07-12-2006 | 03:37 PM

Pat McPherson

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From: Ivoryton, CT

Re: 7.4L cam

I've got one I pulled out of my 1989 7.4 years ago.
If someone wants it, buy me a drink, and pay the shipping.

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Patrick

07-13-2006 | 09:11 AM

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From: On A Dirt Floor

Re: 7.4L cam

Quote:

Originally Posted by MadMat

Sounds like one of those old Buick 455 cams. LOL !

The guys above gave you the right info. I have a little more info in my notes:

Standard Flat Tappet (oval heads)

.004” 287*, 302
.006” 278*, 289
.050” 214*, 218*
.200” 111*, 119*
Valve lift with 1.7 .460” , .480”
ICL 110 ATDC
ECL 118 BTDC
114 LSA

Last edited by SB; 07-13-2006 at 09:35 AM.