Cam Timing
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Teching In
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Cam Timing 04 Sierra 4wd 5.3 with 3.73 gears frequent towing up to 5000lbs gross. Time for a preventative maint rebuild after rolling over 400,000 miles on the original engine. LM7 .040 over flattops 10.3cr static. Bought the 8727R1 cam. Based on published numbers I get 110.5 ICL and 113.5 LSA. I am curious if anyone is running this with more than the +3 advance. My brother with a similar but not 4wd is using the 8718 cam and finds the rpm range is higher up than he prefers after a straight up install. TIA
TECH Fanatic
Joined: May 2016
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From: St. Louis
With less duration 200/205 vs 205/217 I wouldn't advance that cam anymore than how it comes ground and good PCM tuning always makes a noticeable difference even with small duration changes from stock are made, lower speed response and driveabillity especially can improve and sometimes feel better than stock when ignition timing values and a properly adjusted ve map better suited to the new valve events (these things tailored for the intended fuel) are put in the tune
Last edited by stockA4; Aug 7, 2025 at 04:10 PM.
Staging Lane
Joined: May 2025
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Advancing the cam usually helps with bottom end torque but reduces top end HP while retarding a cam helps top end HP while reducing low end torque. But from my experience and most other engine builders will admit that it does way more to torque than HP. Advancing 2 deg can help give 25 ft/lbs more torque but only kills 2-5 HP while retarding the cam 2 deg will do the opposite. Usually on most LS’s until you get in the 0.650 lift range you USUALLY don’t have to worry about valve to piston clearances. But I would still check it if you change the timing.
PS I’m basically running the Summit 8728r cam with 2 deg added advance. Mine is actually the 190395-10 Howard’s cam but it’s close to the Summit cam. Just has a little more lift (.612/.624) vs (.600/.585) and had plenty of room w/ flattop pistons.
PS I’m basically running the Summit 8728r cam with 2 deg added advance. Mine is actually the 190395-10 Howard’s cam but it’s close to the Summit cam. Just has a little more lift (.612/.624) vs (.600/.585) and had plenty of room w/ flattop pistons.
Last edited by MudDAWG; Aug 7, 2025 at 08:19 PM.
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Teching In
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Thanks for the response stockA4. I went ahead and set it up with a 110.5 ICL. A tune is definitely in the plans right after break in and first oil service. MudDawg, true that. I looked at the numbers after degreeing at +2 and felt more comfortable with the 110CL for now. When I get back to my shed in TX I will run some numbers thru Dynomation and see where I get the largest area under the torque curve. My brother will be moving his 8717R1 +2 to see if he can bring his powerband down. He went with the smaller cam as he lives in SoCal and must deal with the smog checks.
