Cylinder Head Swap

Discussion in 'Street/strip 400/430/455' started by CenturyWagon, Mar 31, 2020.

  1. CenturyWagon

    CenturyWagon Member

    Currently running a refreshed '76 455 with stock heads and pistons. I have found a set of 1237661 heads locally, they are bare heads in which i would have to rebuild.

    My '76 heads already have been freshened up with new stiffer TA valve springs, all the valves are the original pieces from '76.

    Can i simply disassemble my '76 heads and swap over everything to the 1237661 heads? Or is there something i am over looking with this potential swap?
     
  2. BrunoD

    BrunoD Looking for Fast Eddie

    In my opinion,you can use all the parts you have in the 76 heads and transfer them into the 69? maybe 71? head,but you have to give the heads yo a trusted machine shop so they can set the surface of the earlier heads.In other words,a small valve job.Bruno.
     
  3. alaskagn

    alaskagn Well-Known Member

    You'd need a valve job for sure at the least just to make sure the valves would seat properly as they should. I'd think everything should swap over though!
     
  4. CenturyWagon

    CenturyWagon Member

    Thanks for the input guys. I came across a link on another site stating that due to the intake manifold face, heat crossover and AIR holes the swap would not be possible. Appears this would not allow installation of any 70-71 heads on a 72 or later block. I am currently running an aftermarket Edelbrock intake for reference.

    https://www.teambuick.com/reference/400-455_differences.php

    Correct me if i'm wrong
     
  5. LARRY70GS

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

    The differences in crossover passages and A.I.R. holes can be overcome. The more important thing to watch is the mismatch between single scallop block/head, and double scallop. Again, not insurmountable.
    head & block solutions.jpg Late block with early heads, just use the right gasket.
     
  6. No Lift

    No Lift Platinum Level Contributor

    I'm pretty sure the '75-76 heads had slightly larger exhaust valves(but not as big as earlier Stage 1 exhaust) so you would definitely need the exhaust seat machined out a little plus the grind on the intake seat to true it up. If you have very low miles on your current heads then they wouldn't need to do anything to the valves, just a final lap-in after the head machining. Have them take a .030" cut off the heads to true them up and for the compression boost.

    There should be no problem using the intake and if those heads are '71 and earlier there are less holes in them to be blocked. Hopefully when you had the '76 heads done all the holes were blocked. No need for heat crossover at all unless you plan on driving on very cold days regularly(<40*). Worse case you drill a 1/4" hole in one of the crossover plugs near the choke coil if you have one in the manifold. No need for all that factory heat.
     

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