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461 Heads on a 283?

Discussion in 'The Hokey Ass Message Board' started by coupemerc, Aug 28, 2010.

  1. coupemerc
    Joined: Jul 16, 2007
    Posts: 406


    I'm rebuilding a 283 for my coupe. Just found out that the combustion chambers on the 461 castings are overhanging the bores slightly. Bore is 3.905". Do you guys run them this way or should I do something different?
  2. Model A John
    Joined: Apr 24, 2008
    Posts: 1,768

    Model A John
    from wichita ks

    Either bore the cyls. to 4.000 or get a pair of 283 heads. Good luck with your project.
  3. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    Member Emeritus

    You do know you're going to LOSE some compression with those heads, unless the pistons have some sort of a dome on them? It would be better to use Power Pack heads, or 416/601 heads from a 305 (58 or 53 CC chambers respectfully). The 305 heads would have slightly larger ports, and either the same size valves as Power Packs, or in some cases, slightly larger valves. It's really not that big of a deal with the "overhang"; just look at the head gaskets. ALL the SBC head gaskets are pretty much "universal", that come in gasket sets. They're supposed to fit "all" SBC engines. There's "overhang", or "underhang" because of that. There are dedicated head gaskets in the after market, aimed primarily at racing you could use, but they do cost more. Bujtch/56sedandelivery.
  4. N2hotrods
    Joined: Jul 6, 2010
    Posts: 146


    The 461 head casting is not the best choice for your 283. The small bore of the 283 will shroud the intake valve. The 461 should have 1.94 intake valve and 64 CC combustion chamber. If you are using the stock flat top pistons you will want a head with 58CC combustion chamber to keep a decent compression ratio. You can use a later model 305 head with the 1.85 intake valve or an early 283 head with 1.72 intake valve. Both heads have a 58 to 60 CC chamber. I have had much success with the 283 using the 305 head and flat top pistons resulting in a 9.25 to 1 compression ratio. I use a steel shim head gasket for the 283 or 305 with a 3.965 bore opening and a .018 crush thickness. The cam will need to be carefully selected for the street the 283 cam must not be to large. With the small bore engine a 485 lift and 220 duration @.050, 110 to 112 lobe separation is about as big as you want to go with an automatic trans. Good luck

  5. coupemerc
    Joined: Jul 16, 2007
    Posts: 406


    Thanks for responding guys. I think that I will replace the 461 heads with the 520 castings and mill the domes off of the pistons that I have. I want the compression ratio at 10/1 with a comp 280H cam. It's a stick car.

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