1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

454 cracked exhaust manifold

Discussion in 'Chevy Trucks' started by 70monte, Feb 25, 2008.

  1. 70monte

    70monte Senior Member
    Messages: 468

    I changed the plugs today on my 98 K3500 with the 454. I noticed that the passenger side exhaust manifold is cracked in three places on the flange between cylinders 2 & 4, 4 & 6, and 6 & 8. The driver's side manifold does not have these cracks.

    I've heard that 454's have problems with cracking exhaust manifolds so I'm guessing these cracks are not normal. It doesn't sound like I have any exhaust leaks. Is this the area that these things are prone to crack at? Anyone know a good source for used exhaust manifolds for these engines? Thanks.

  2. wild bill

    wild bill PlowSite.com Addict
    Messages: 1,239


    yes this is a problem ! i do not think you can find used manifold's that are any better than what you have ,try to look for a after market manifold .
  3. 70monte

    70monte Senior Member
    Messages: 468

    I found some new aftermarket exhaust manifolds for the 454 on Ebay. They have the same cracks in the flange as what my manifold has. I guess its just how its made and mine must be normal. Thanks.

  4. 70monte

    70monte Senior Member
    Messages: 468

    I looked at my driver's side manifold and it also has these cracks in the flange. It must be how these were designed.

  5. powerjoke

    powerjoke PlowSite.com Addict
    Messages: 1,341

    these things cracking are normal

    if i remember right in about 1989-199? they had a 2 peice manifold to try to help with this problem but i don't know if it worked or not

    regardless i would recommend factory stuff, the oval exhaust ports are a little diff. to find for youre truck and then you would have to drill the o2 sensor hole.....unless a aftermarket company for-seen this and is now making a direct replacement?
  6. willofalltrades

    willofalltrades Member
    Messages: 97

    Put some Headers on that baby!... thats the only solution my dad's friend (chevy nut) offered to me.
  7. 70monte

    70monte Senior Member
    Messages: 468

    After having headers on my 1970 Monte Carlo years ago, I don't think I ever want to have them again. I was always burning up my plug wires and plug changes were a four hour ordeal. Plus they were always loosening up and they finally burnt up my starter.

    I know that headers these days are probably better than the ones of the 80's but my bad experience with them is not easily forgotten. It appears that my stock manifolds are okay for now so I will just leave them alone for now. Thanks.