exhaust manifold - bolts or studs?

Discussion in 'Street/strip 400/430/455' started by 12lives, Apr 17, 2019.

  1. 12lives

    12lives Engage! - Jean-Luc Picard

    When I took my exhaust manifold off I had bolts holding the down pipe to the manifolds on both sides. I notice in the assembly manual that OEM used studs/nuts on the drivers side and bolts on the passenger side for the GS and GS455. Interestingly, it is reversed for the Skylark 350.
    So, should I used bolts on both sides, studs/nuts on both sides, do like the assembly manual, or it doesn't matter? If I use studs should I go with the ARP stainless stud with their special nut?
    What say you???
  2. hugger

    hugger Well-Known Member

    s-l300-1.jpg Studs, with brass nuts available at any parts store

    Or a steel flange locknut

  3. Schurkey

    Schurkey Silver Level contributor

    Brass nuts on studs! I never use steel nuts on exhaust manifold studs on anything I owned. If you have to use steel fasteners, be sure to use anti-seize.

    "I" would be very likely to investigate and try to "reverse engineer" what logic the factory used when putting studs in one side and bolts in the other. If there is no logic--and that seems unlikely--then studs and brass nuts on both sides.

    NAPA--and probably every other parts store--sells various lengths of studs and nuts in blister packs for way too much money.
  4. hugger

    hugger Well-Known Member

    The reasoning behind the one bolt was the exit angle if the pipe would make a stud a little more aggravating to get a deep socket and extension on therefore they went with the bolt. I myself just used a shorter stud and with a wiggle and deep well all is good again
  5. agetnt9

    agetnt9 Agetnt9 (Dan)

    Studs with longer brass nuts and steel washers are good. and can heat them up to get them off in 20 years.
  6. TrunkMonkey

    TrunkMonkey Well-Known Member

    Milk of Magnesia is a good locker and anti-sieze for "hot" areas.

    We used it to hold lots of jet engine hot sections together, and make it easier to get them apart again.

    Thanks MOM!
  7. 12lives

    12lives Engage! - Jean-Luc Picard

    Oh yeah - Milk of Magnesia - even has a USAF part number!

    So no stainless? Any tricks to keeping the stud from becoming a rusty stick?
  8. 65Larkin

    65Larkin Well-Known Member

    When I remembered what Mum used it for I almost pooped :)

    It never ceases to amaze me the myriad uses for everyday things out of the pantry or medicine cabinet.
  9. 12lives

    12lives Engage! - Jean-Luc Picard

    And it's in an article in the June 2019 Street Rodder rag, page 112 - small world!

    Ayway, I settled on these for the studs - $5: Part #: NOE 6001816 Product Line: NAPA Solutions (grade 5)
    Of course they come in three's - looks like I will have a spare pair!
  10. copperheadgs1

    copperheadgs1 copperheadgs1

    What year you talking? All 70-71 and probably 72 GS 455 used all bolts. No studs were used. Maybe bigs used studs but not GS. You are chasing the wrong rabbit if you are working on a GS 455.
    Last edited: Apr 28, 2019
  11. copperheadgs1

    copperheadgs1 copperheadgs1

    2B5C5B92-F442-4BEA-8840-F2CF084C5F86.jpeg Not sure what you have for an assembly manual. But here is a 70 Assembly manual. Proof is in the pudding. Only 350 used studs on right side only. GS455 and it’s all bolts baby!
  12. copperheadgs1

    copperheadgs1 copperheadgs1

    Also you say your assembly manual says studs on drivers side where my assembly manual I posted shows right side not drivers but again that’s 350 only!
  13. 12lives

    12lives Engage! - Jean-Luc Picard

    Thanks Dave - your manual is much clearer than mine, which is a copy of a copy of a copy. Interestingly, I also checked my "Millenium" 1972 manual and it shows bolts for both sides, single or dual, 350 and 455! So I guess Buick later decided the bolts were better for all applications.
    Last edited: Apr 28, 2019
  14. copperheadgs1

    copperheadgs1 copperheadgs1

    It’s funny because studs are easier to use laying on your back. Nothing to line up like bolts. The studs hold the pipes in place for you. Ah the price of correctness.

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