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Hot Rods Head swap question

Discussion in 'The Hokey Ass Message Board' started by bob8823, Aug 5, 2014.

  1. bob8823
    Joined: Apr 16, 2011
    Posts: 39

    bob8823
    Member

    The heads on my motor came off a 68-69 307 sbc. I have a set of heads from a 63-67 283 that are completely rebuilt, all new valves, springs, studs, etc. Any reason why I can't swap heads. Are the push rods the same length. Here are the head numbers.

    3911032 68-69 sbc 307

    3795896 63-67 283 sbc

    Block # is 3756519 58-62 283 sbc

    Thanks for any help.

    Bob
     
  2. aaggie
    Joined: Nov 21, 2009
    Posts: 2,531

    aaggie
    ALLIANCE MEMBER

    The heads will bolt up but check the bolt lengths. For some reason I remember that there are two that are shorter. Push rods and rocker arms should be the same.
     
  3. Mr48chev
    Joined: Dec 28, 2007
    Posts: 28,586

    Mr48chev
    ALLIANCE MEMBER

    We ran a set of 283 power packs on a 307 we put together with a mid 70's swap meet Z28 cam in it and that little bugger ran like a bandit. My son had it in a 70 Chev pickup that he street races some and I ended up driving the pickup to Texas and towing a loaded trailer back with it. I'd think you will be happy with the "stroker 283" when you get it done.
     
  4. bob8823
    Joined: Apr 16, 2011
    Posts: 39

    bob8823
    Member

    Both heads look exactly alike, there are two shorter bolts. The reason I am questioning the push rod length is because I had to really loosen up the rockers to get them in. Seemed like more than usual. Thought maybe the push rods
    were longer. Only have the push rods that are in the motor now, don't have the push rods I used with the rebuilt heads, so I can't compare them.
     

  5. Mr48chev
    Joined: Dec 28, 2007
    Posts: 28,586

    Mr48chev
    ALLIANCE MEMBER

    I can't remember what push rods we used but they were some that had come out of another engine as we didn't buy much new for that engine. Who ever did your heads may have run the rocker nuts way down on the studs so that isn't a biggie as long as the rockers aren't at odd angles with the valves closed.
     
  6. bob8823
    Joined: Apr 16, 2011
    Posts: 39

    bob8823
    Member

    So you think going with the 283 heads with the smaller CC's would be the way to go. Thanks for the help.
     
  7. 327Eric
    Joined: May 9, 2008
    Posts: 1,527

    327Eric
    Member
    from Diablo Ca.

    its all the same. The 2 shorter bolts go on the outside edges, by the oil drainback holes, under the valve covers. bolt em on and go. If you are running a long water pump, you will have to change your alternator mount set up, due to the lack of accessory bolt holes. Smaller chambers, small ports and valves, should work better with the low end torque.
     
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 48,003

    squirrel
    Member

    I always take rocker arms off before installing heads...if someone tightened the rocker nuts, then you'd have to back them off to put the heads on, right?
     
  9. Those 307 heads have 76cc chambers and get you 8:1 if your lucky with the swept volume of a 307. They are shitty on a 307, I can't imagine how awful they'd be on a 283.
    Put the 283 heads on your 283 and probably won't believe the difference it will make.
    The 305 ho heads work pretty good on a 283 too if you want accessory holes on your 283.
     
  10. indyjps
    Joined: Feb 21, 2007
    Posts: 4,105

    indyjps
    Member

    The 283 heads are a step in the right direction, the 307 heads were terrible large chamber tiny valve deals. Pushrods for all small block Chevy "should" be the same. Hard telling if the block has been decked or heads milled. Assemble it all, turn the engine by hand and verify if the pushrod is binding and make sure the pushrod is contacting the rocker in the cup thru the lift range.
     
  11. bob8823
    Joined: Apr 16, 2011
    Posts: 39

    bob8823
    Member

    Thanks for all the help guys, I appreciate it. Tomorrow the 283 heads go on. I'll update this thread once I
    get it running, should be by the weekend.
     

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