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  1. #1

    Default 2003 Sierra Heads

    Sorry about the hiatus lately guys. Been working 12+ hours a day on the dang ship and dealing with a new addition to the family and the wife. Now before anyone thinks we had a kid, no its a purebred Golden Retriever. I'll put pics up in the coffee shop.

    But for my question, I found a pair of heads that supposedly came from a running engine from a 2003 Sierra 5.3 for 85$ for both of the pair. I know my engine is getting old and is starting a case of the early morning/cold weather knock. Would heads from a 2003 5.3 fit a 99 5.3 engine?

    Is it worth buying and swapping them out at all?

    If at first you don't succeed, get a bigger cheater bar.

    1999 GMC Sierra SLT Z71 | 5.3 "Vortec" | Spectre "Cold Air Intake" | TransDapt TBS | Hypertech 30005 Tune | 2005 Chevy Tail Lights | Denali headlights | Grill Mounted Fog Lights | AWS Bug Shield | 265/70/16 Futura Scramblers | Boss HD Speakers | 2005 Overhead Console | Flowmaster Super 40 mufflers 2N1O | Mostly stock-ish
    Bigger Amp Alternator | Electric Fans | Transmission Fluid cooler | Paint (Halfway there)| Interior Restoration/Upgrade with newer model parts | Window Visors (In channel) | Tint | Low-Profile Tool Box | LEDs throughout stock cab locations (68% Done) | And whatever is spurr of the moment
    CVN-69 "IKE-ATRAZ" AIR/V-2 Gear Dawgs

  2. #2


    Not sure what new heads would buy you, the knock is probably probably cold piston slap, or lifters that have bleed down over night. Both are in the block.

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  3. #3


    the heads will fit but like rayvoy said probably wont do much..
    2000 single cab short bed 1500 w/ 6.0 vortec maxx swap from a 2006 2500, custom intake, slotted brakes, shorty headers, 8mm wires, electric fan, strait piped, 4.5 inch lift, asp pulleys, true dual through body exhaust, built trans w/ shift kit, custom tune ... 320rwhp

  4. #4


    i would not bother. Plus, before I installed the used heads I would have them checked to make sure that they are not warped or cracked. Then I would have them rebuilt with new valves and valve seats, maybe even a 3 angle valve job. No point in changing something that is working with possibly the exact same part that may not work. I would at least go for an upgrade. if you do buy them make sure they are not the castec heads with the 706 stamp. here is how to identify them.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  5. Likes zuki82 liked this post
  6. #5
    Jr. Engineer
    Join Date
    Oct 2013
    weedsport, NY


    what pikey said!!! If you do get them, at least get them upgraded first! Angle grind, valves, shaved,,,,,

  7. #6


    Well wound up not getting them. I need to behave with my money for right now. If I do anything in the future, it may just be a partial rebuild of the bottom end, all cleaned out and such. But I'm not even sure if that would happen before the truck goes kaboom. Got 259,824 on her now as I am looking at it. Would love to go to 300,000 before I start heavily thinking about new truck time. Gotta pay off this dang dog first.

  8. #7


    My '09 has cold morning piston slap (it would go away after 30 seconds). I have always used synthetic oil; but a little while ago (maybe 2 oil changes) I started to use Royal Purple, the cold morning slap has disappeared.

    Was it the RP oil, I don't know; but it is gone.

    Maybe an oil change (as in type and brand) might help.

  9. Likes rileyjr16 liked this post
  10. #8


    Think that might be my problem. Always ran Mobil1 5w-30 through it. Change to Valvoline for one change and changed weights for winter. Actually my thing just came on so Saturday, I'm gonna jack her up and change her.

  11. #9


    Quote Originally Posted by rileyjr16 View Post
    and changed weights for winter
    That's probably your problem, the "weight" should not be changed for the winter. Run the 5-30 all year round.

  12. #10


    Thats when i started hearing it more and more often is after I changed. Now I let y truck warm up before I leave. But with 5w-30 it wouldn't do it every cold morning like it does now and not for as long. Maybe 30 seconds.

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