430 and 455 exhaust manifold differences

Discussion in 'A boatload of fun' started by inverse121, Oct 10, 2022.

  1. inverse121

    inverse121 Well-Known Member

    I have a 68 Electra and am in need of a driver's side exhaust manifold.

    It didn't take me long searching to figure out that the 67-68 manifold is different, but I am not familiar enough to know if the 69 430 or any of the 455 manifolds will work well enough or if its matter of angle of exit.

    I do not want to change to headers and I am not worried about a couple of horsepower one way or the other.

    Can someone please school me on years that will work as a simple replacement?
  2. David Hemker

    David Hemker Well-Known Member

    To the best of my knowledge regarding the drivers side exhaust manifold:

    67 is a 1 year only casting and requires use of a doughnut or the factory heat riser valve to
    force hot exhaust gases to go under the intake until the engine is warmed up
    68 -69 are the same and have what looks like a handle above the center ports and require the
    doughnut or valve mentioned above. The handle is part of the shield used to direct
    warm air into the air cleaner for cold weather warm up.
    70-74 appear the same without the handle mentioned above with the doughnut for the pipe
    sealing cast on it. Uses a different shield to direct warn air into the air cleaner as
    mentioned above.
    75-76 appear the same without the handle mentioned above and require the use of a
    doughnut or valve mentioned above. Uses a different shield to direct warn air into the
    air cleaner as mentioned above.

    All will bolt on, interchange and exit in the same location.
    Last edited: Oct 11, 2022
    PGSS, SpecialWagon65 and inverse121 like this.
  3. inverse121

    inverse121 Well-Known Member

    Thank you David, I think that will make my search much easier.
    I am not overly concerned with factory originality or keeping the heat riser.
    It would appear that I have the 68-69 with the handle. It has a heat riser valve that has been brazed to be a "donut" of sorts.
    Now if I can figure out how to get the exhaust manifold off with the engine in the car without breaking any of the manifold bolts.
    There is enough rust on the bolts that a 9/16" wrench/socket is slightly too big and a 1/2" wrench/socket is way too small

    1968 Buick Driver Exhaust Manifold.jpg
  4. Duane

    Duane Member

    I believe I have a 68-69 400/430 driver side exhaust manifold. This would be the manifold only, I do not have the valve piece at the bottom.

    I am located outside the Philadelphia area, where are you located?

    Shipping is expensive.
    inverse121 likes this.
  5. inverse121

    inverse121 Well-Known Member

    Thank Duane. I am in Central NY. Philly is about a 4 hour drive one way. Shipping would make more sense. I could reuse my valve piece, its not part of my problem.
  6. Duane

    Duane Member

    I will see if I still have pics of the part tonight, and if so will post them here.

    I don’t think I was asking much for the part.

    I just shipped one of these from Phila to Baton Rouge and the shipping cost more then the part.
    Last edited: Oct 11, 2022
    inverse121 likes this.
  7. Max Damage

    Max Damage I'm working on it!

    The manifold bolts actually pass through the heads, so find the end of these bolts, scrape them with a dental pick or some other sharp tool, and then put penetrant on them and let them sit before using force. Also, when it comes time to remove the bolts, tapping or impact is much less likely to break the bolts.
    455 Powered and inverse121 like this.
  8. inverse121

    inverse121 Well-Known Member

    Thank you, this is very helpful, I did not know they all passed through the heads. I've been soaking it down with PB Blaster, next time I am at NAPA I will spring for some Kroil or maybe whip up a batch of ATF & Acetone and start painting it on.

    I don't think I will be able to get any sort of impact driver on them, but I might be able to tap on them. I'm going to have to get creative on a wrench or socket to fit the rusty head.
  9. telriv

    telriv Founders Club Member

    Try a 14mm wrench which is slightly smaller than 9/16ths. OR a 13 mm wrench that is slightly larger than 1/2".

    Tom T.
  10. gsfred

    gsfred Founders Club Member

    Got it. PM with pics sent.
    inverse121 likes this.
  11. TORQUED455

    TORQUED455 Well-Known Member

    Chris, what is wrong with the down pipe? If you are uncomfortable in tackling the job, I own an auto repair shop in Baldwinsville and can handle the work for you. My days of licking door handles are done, but this shouldn't be a big deal at all. Message me if interested.
    inverse121 likes this.
  12. TORQUED455

    TORQUED455 Well-Known Member

    BTW, if you want my help, please don't attempt to get those bolts out yourself. I don't like working behind stuff like that! Kroil, Blaster, ATF-acetone are a waste of time until you get the bolts broke free. Heat is your friend here, miniductor or oxy/acetylene torch and a water bottle.
  13. inverse121

    inverse121 Well-Known Member

    This is a great forum. I really appreciate all the help.

    Fred I’ll be in touch via PM thanks.

    Bob, I’ll send you a PM for contact info. I understand your instructions/position on penetrant.

    Here is a link to my post about why I now need a manifold. They probably did not use a torch.
    Another new guy in NY
  14. Duane

    Duane Member

    Here are the pics of my manifold.

    69M1.JPG 69M6.JPG 69M7.JPG
    inverse121 likes this.
  15. inverse121

    inverse121 Well-Known Member

    Just wanted to send a big thanks out for all of the help on this one. She's nice and quiet now.

    Turns out Fred and I used to be neighbors. Bob fixed the exhaust for me this week and cleaned up my plug wires with a set of wire holders as a bonus.

    Bob's shop is clean enough to perform open heart surgery! Its a really nice operation with friendly people. I appreciate him squeezing me into his schedule.
  16. TORQUED455

    TORQUED455 Well-Known Member

    Chris, we are glad you are happy with the outcome, and it was good meeting you. The key to getting those bolts out in one piece is 1). Clear your schedule, not a job you want to rush and 2). Torch and water bottle. The last thing you want to do is break one of the bolts off. That would be really bad news. Lots of heat/cool cycles. 3 or 4 of them took 5 or 6 cycles each, but ironically the long center one came right out. Another trick is to make the breakaway turn clockwise, tightening. Once they were broken free, I used Kroil, and again you have to be careful. You can still break one off at this point if you are not careful.
    Max Damage likes this.
  17. TORQUED455

    TORQUED455 Well-Known Member


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