Chevy 350

Discussion in 'Inboards' started by mikealston2428, Aug 3, 2016.

  1. mikealston2428
    Joined: Jul 2011
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    mikealston2428 Senior Member

    Hi all,
    Oklahoma I've a Chevy 350 and would like to know if it's a vortec
    How can I tell ?
    This question has come about because I need to find out the best spark plugs for my engine
    I've read i need to find out the year of the heads to choose the correct plugs
    I want to use Autolite plugs
    From what I've read it the AP85 if the heads are older than 1970 and either the 25 or 26 plugs if newer than 1970
    Cheers
    Mike
     
  2. charlief1
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    charlief1 Junior Member

    Chevy had several head designs from the mid 50's to 2000. Is the engine carbed or injected? The vortex heads were used on injected engines and while there were a few after market intakes to mount a carb on them I don't believe there was ever a factory 4 barrel intake made. Take the casting number off the heads and google it as "chevy head casting number *******.
     
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Vortec engines are pretty easy to identify. First off it will not have a mechanical fuel pump boss on the front left side of the engine. The casting will not be milled out in this area. The valve covers are centerline bolted, not perimeter bolted, but the big tell is the number of intake bolts (8 on the Vortec).

    All Vortec heads were designed for EFI, though there are a few different castings. These break down into the early Vortec (L31), the PP series, which have small or large valves and the fast burns, which are aluminum.

    If you're going to use first gen heads, the double hump 202's are the usual choice for performance and flow, though the stock smog hump equipped L31 Vortec, out flow these puppies right out of the box.

    Don't use autolite plugs, just bite the bullet and use E-3 plugs. Depending on which head you have it'll be an E-40, E-42 or E-62 (Vortec). You never need to gap them, they'll outlive the boat (and you) and will fire no matter what. Yeah, they cost 3 times as much as a good plug, but it's the last plug you'll buy for this engine.
     
  4. mikealston2428
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    mikealston2428 Senior Member

    This is the manifold guys
     

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  5. mikealston2428
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    mikealston2428 Senior Member

    Another picture
     

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  6. mikealston2428
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    mikealston2428 Senior Member

    Hopefully these picture may help to ID engine
     

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  7. mikealston2428
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    mikealston2428 Senior Member

    Another picture
     

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  8. mikealston2428
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    mikealston2428 Senior Member

    Rollers
     

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  9. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    [​IMG]
    . . . vortec head, note the intake bolt locations.
    [​IMG]

    . . . first gen and LTI head, again note the intake bolt locations.

    Your heads are first gen, not Vortec.
     
  10. charlief1
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    charlief1 Junior Member

    Standard old school chevy. Looks like single humps.
     
  11. mikealston2428
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    mikealston2428 Senior Member

    Hi Guys,

    OK excuse my lack of knowledge.

    General 1 single hump

    Any idea of the age ?

    Thanks,
    Mike
     
  12. mikealston2428
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    mikealston2428 Senior Member

    Hi Par,
    Are you referring to E3 Spark Plugs Diamond Fire

    Thanks,
    Mike
     
  13. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Yep, E-3 plugs. Yours will likely be E40 or E42's.

    The age of the head can be gotten from the casting number. There are heads to avoid and some that are much better than others, so pull the casting numbers and look them up on one of many sites that specialize in SBC heads (> http://outintheshop.com/faq/casting/heads.html <)
     
  14. keith_2500hd
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    keith_2500hd Junior Member

    realize also that for boat, unless full-on jet or flat bottom, the large ports are not that good. they normally run 195cc intake port, or truck spec cylinder head. you want the torque not horsepower. the vortec head and intake will bolt on to early blocks, good for 20-40hp, depending on setup. mercruiser went from 260 to 300hp with vortec, realize that roller cam of vortec block added some hp also. there are websites breaking down swap.
     

  15. mikealston2428
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    mikealston2428 Senior Member

    Casting Numbers

    OK so here's an picture of head casting number
    Its 3832441 or maybe but don't think so 3882441

    I've had a look at a number of sites and can't find this casting number?

    Thanks
    Mike
     

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