430 heads / exhaust crossover plugs

Discussion in 'Street/strip 400/430/455' started by 83T-type, Oct 14, 2017.

  1. 83T-type

    83T-type Well-Known Member

    IMG_2553.JPG IMG_2554.JPG IMG_2551.JPG I just thought I'd share a tip to plug the exhaust crossover on 430 heads. This may work on more applications, depending on the exhaust crossover style. In this case they are convienently straight and already the right size to make it easy.

    The holes were about .735". I tapped these with a 3/4-10 tap. I found some 3/4-10 aluminum threaded rod and cut them to 3" sections and slotted the tops so I could use a flathead to screw then in. If more time was spent opening up the exhaust port side you could tap all the way through and blend the port smooth. In my case I just wanted them blocked as much as possible since these heads aren't ported.

    I used a little jb weld lightly smeared on the top 1/2" of the threads just to hold them in tight (probably not really needed)
     
  2. Stevem

    Stevem Well-Known Member

    Yes Sir, that would be the way I would do it followed with some ciramic Epoxy to reshape the back wall of the bowl on the center Exh ports!
    Letting the Epoxy form about 3/8" of that threaded hole would be a good idea also!
     
  3. 83T-type

    83T-type Well-Known Member

    I always wondered if there was an epoxy that would work in an exhaust port. I haven't seen it done, but ceramic would make sense. Anyone use it?
     
  4. Stevem

    Stevem Well-Known Member

    Yes, used it and worked as stated, but it's not that cheap!

    coltronics makes and sells it.

    Where a big plug of stuff is needed ( not like in Buick heads) I use hydraulic cement as a cheap tub of it will last a life time and with a little practice I can reform the rear wall of the valve bowl to a perfect shape before it sets up.
     
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  6. Thumper (aka greatscat)

    Thumper (aka greatscat) Well-Known Member

    If using iron intake manifolds I use small freeze plugs lock tighted in place. then drill a 1/8" hole in each only on the passenger side to give the choke some heat to operate properly.
     

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