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8.1 Cam Swap. Head Work

yukon25008.1

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yukon25008.1 Senior Enthusiast

yukon25008.1

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besides the tune, ehaust, and intake im thinking id like to play with the cam andheads a little, its an 04 yukon 2500 8.1 4l85E, i have a spare 04 8.1 in the shed for parts. just curious what cam is good for daily drivers, also what else has to be changed. valves? valve springs, lifters?.

please let me know what you think

yukon25008.1 Senior Enthusiast

yukon25008.1

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spoke with someone at jegs yesterday, comp cams offers a high energy mild/mid range cam, and just requires roller rockers,

Z'06 Enthusiast

Z'06

Posted
Posted

Any cam change requires upgraded springs and hardened (chromemoly) push rods. Which springs you choose has a lot to do with the lift of the cam you choose, as well as its lobe profile. You don't need to worry about upgrading rockers (though you might consider strengthening your stock rockers with a rocker arm trunion upgrade), and not being a GMT900, you don't need to worry about pulling the heads to upgrade weak lifters.

 

You will find a LOT more info on cams at PerformanceTrucks.net than any other forum.

yukon25008.1 Senior Enthusiast

yukon25008.1

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I started pulling the project 8.1 in the garage apart and found roller lifters, so do you guys think the oem roller lifters are ok, i realize i will have to change the rockers and pushrods, also what about the springs.. or will that depend on the cam

Z'06 Enthusiast

Z'06

Posted
Posted
I started pulling the project 8.1 in the garage apart and found roller lifters, so do you guys think the oem roller lifters are ok, i realize i will have to change the rockers and pushrods, also what about the springs.. or will that depend on the cam

 

Spring selection depends on the cam's lift and its lobe profile. Stock lifters should be fine. Shouldn't have to change the rockers either.

yukon25008.1 Senior Enthusiast

yukon25008.1

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how much cost do you think would be involved in having the heads and intake polished to help with airflow? before the cam..

Z'06 Enthusiast

Z'06

Posted
Posted

A lot, considering a cam swap would make a huge difference for a lot less work. Yes, porting and polishing heads may help, but those big block heads might already flow pretty well.

 

I saw you took this thread over to PT.net - good move. You might want to download Comp Cams' free cam selector software for some ideas.

Matt427 Enthusiast

Matt427

Posted
Posted
no, i figure that would be the last thing, right?

 

Sorry, I forgot to get back to this thread. I would suggest getting the tune first, because you may be happy with the performance with just a tune. I was a little disappointed in the performance of my 8.1 Sub, especially when compared with my 5.3 YukonXL. Sure it could pull the camper a lot easier than the 5.3, but everyday driving seemed sluggish. After the Blackbear tune, there was a huge difference. It woke up that 8.1 for sure! The best part is that it only cost $250, which is chicken feed compared to the cost of a new cam and head work.

yukon25008.1 Senior Enthusiast

yukon25008.1

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Thanks guysfor the reply,s I wasnt ready to spare the expense for porting, just would like to have openings cleaned up a little.. rough edges. im checking with comp now.

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