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thinking 305 heads on my 350.....

Discussion in 'Chevy C/K Truck Forum' started by jroc, Mar 17, 2014.

  1. jroc

    jroc New Member

    Just wondering if anybody has done this recently? I have a 90's TBI 350 with bad head gasket looking to swap for 305 heads for more power. Aside from the mileage difference any other pros and cons to this?
  2. BurbanMan

    BurbanMan Member 1 Year 500 Posts

    You will get a compression gain, but your going to lose flow. All in all, IMO you would be p!ss!ng in the wind...
  3. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    That's been a performance upgrade suggestion for a long time. Apparently, the 305 heads increase compression, which increases power output. How much difference it makes, I don't know.

    I do know, there was two different 305 heads, one has a smaller combustion chamber volume. It's not much, maybe 6 to 8 cc, but I do know one works very well and the other can cause problems (sorry, I don't remember which one is the best one). The casting numbers will help to identify them, look under the valve covers.

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