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Gmc six info needed.

Discussion in 'The Hokey Ass Message Board' started by edweird, Feb 3, 2011.

  1. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

    Anybody in hamb land running one of these ? Me and my dad are picking up a 270 sat. I would like to see pics of them souped up. Thanks
     
  2. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

  3. Patience Grasshopper!

    There HAVE to be some GMC guys on here... and if you give up on it, I'm looking for 270 pistons :D
     
  4. Deucedreamer
    Joined: Jan 11, 2010
    Posts: 540

    Deucedreamer
    Member
    from BC Canada

    I have a GMC 302 with a 6-71 blower and dual carbs. Basically the same engine just a larger bore. In fact my 302 is running a 270 crank and rods. Although everything else is 302. Here's a pic.
     

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  5. merc-o-madness
    Joined: Aug 23, 2004
    Posts: 1,544

    merc-o-madness
    Member

    damn i would like to hear how that sounds
     
  6. badsix
    Joined: Sep 26, 2010
    Posts: 108

    badsix
    Member
    from oregon

  7. Wow! that thing is cool!! what kind of hp / tq does it put out?

    add -
    heh 2 blown 6's that looks a little odd with the blower not in the center though. but i LOVE it :D
     
    Last edited: Feb 3, 2011
  8. badsix
    Joined: Sep 26, 2010
    Posts: 108

    badsix
    Member
    from oregon

  9. RichFox
    Joined: Dec 3, 2006
    Posts: 10,005

    RichFox
    ALLIANCE MEMBER

    A couple of mine. I asume you have joined Inliners International?
     

    Attached Files:

  10. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

    i have wood !!!!!
     
  11. OldBuzzard
    Joined: Mar 8, 2008
    Posts: 878

    OldBuzzard

    Go to stoveboltengineco.com click listen It's a 302 but worth listenuing to.
     
  12. Deucedreamer
    Joined: Jan 11, 2010
    Posts: 540

    Deucedreamer
    Member
    from BC Canada

    I don't actually know how much HP/TQ it puts out, I've never had it on a dyno. But my engine builder guessed that with 5lbs of boost, which is what I run as it's a street engine, that it probably puts out in the neighbourhood of 260-290 hp. It pulls really well. I was doing 50 on the hwy and wanted to pass a big truck, so I stepped on it and was doing 80 before I knew it:D. It really moves. Personally I like the blower off to the side. That's part of what makes it different.

    It sounds really nice. I have nicson knock off cast iron headers, dual exhaust and smitty mufflers. So it rapps quite loud on deceleration and sounds awesome under power.

    Edweird: If you're interested in the specs of the engine you can pm me, i'm not sure too many others on here are that interested...lol
     
  13. quicksilver
    Joined: Mar 12, 2007
    Posts: 11

    quicksilver
    Member

    I'm interested! Post the specs up. I'm in the early stages of building a GMC 302 for my 35 Ford pickup.
     
  14. RichFox
    Joined: Dec 3, 2006
    Posts: 10,005

    RichFox
    ALLIANCE MEMBER

    Hey Quicksilver. I'm in San Mateo and ran my GMCs at Bonneville and such for a number of years. Still have a El Mirage record. Your project sounds pretty interesting.
     
  15. quicksilver
    Joined: Mar 12, 2007
    Posts: 11

    quicksilver
    Member

    I've read a number of your posts while doing research about the inline GMCs. I've love to get together to pick your brain and learn about these engines sometime.
     
  16. Deucedreamer
    Joined: Jan 11, 2010
    Posts: 540

    Deucedreamer
    Member
    from BC Canada

    Ok, so when I was looking for a 302, I had a really tough time finding one. Being from BC Canada, there's not much in the way of these old engines up here. So I ended up buying a complete 270, a bare military block and a complete 302 head. Since the 270 has the same stroke as the 302, I used the rods and crank from it as well as the camshaft and a few other parts like the oil pan water pump etc. There's not much difference in the military blocks, other than a few more bosses and threads for PTO's and stuff as compared to civilian blocks. I would have liked to have a cross flow head too, but once I started doing research into them, I realized that was a pipe dream considering the rarity and cost. Even the Arias ones are expensive.

    Compression: 7.8-1 Arias forged aluminum flat top pistons
    Stock rods and crankshaft
    Stainless steel valves and pushrods: 1.84" intake and 1.6" exhaust
    The head has been ported and polished
    The camshaft was reground by a local grinder with a conservative grind as it is driven on the street as well as blown: .309 lift intake, .295 lift exhaust with 113 degrees of lobe separation.
    The ignition is a dual point mallory unit with an MSD box hidden behind the seat.
    Dual Edelbrock 600cfm carbs
    Philips Performance cast iron headers (nicson knock offs)
    The blower manifold is actually a cast aluminum 4-71 unit that is supposed to mount the blower vertically that I got from the old Stovebolt engine co. It was his last one which he found at the very back of a dusty shelf. I had a machine shop build and adapt an aluminum plenum(with a pop off valve)to the manifold so that the blower mounts horizontally.
    The Valve cover is a two piece unit that I found at the Portland Swapmeet. Apparently only 60 were made as the guy making them couldn't make them pay for themselves. I only paid $60 for it and it was his last one.
    The side cover is a custom finned one I had made as vintage finned aluminum ones are fairly rare.
    A lot of the pieces on the engine were custom made to make it all fit and run right. It cost me 3 times as much as I thought it would and took me 5 years to build, mainly cause of money. That's about it.
     
  17. Hawaiianstyle
    Joined: Jul 8, 2009
    Posts: 113

    Hawaiianstyle
    Member

    Hey Deucedreamer, I hope you dont mind but I re-posted your Specs (and photo) over on the "The Ultimate 235 Hop up Thread....... "

    I am sure those guys will get a kick out of your engine build.
     
  18. Hawaiianstyle
    Joined: Jul 8, 2009
    Posts: 113

    Hawaiianstyle
    Member

    BTW, Killer mill.
     
  19. 50ChevyFrank
    Joined: Sep 5, 2007
    Posts: 229

    50ChevyFrank
    Member

  20. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,385

    GMC BUBBA
    Member

    hERES A PIC OF MINE..

    29 Model A sedan made into truck. 302 GMC bored .125 for a 322 cu in.
    Howard camshaft,Jahns pistons, Nicson headers , four speed with quick change. Have driven for the past six years ...been a good one AND its fuel injected , TBI hidden under the air cleaner...........
     

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  21. SinisterCustom
    Joined: Feb 18, 2004
    Posts: 8,269

    SinisterCustom
    Member

    GMC 6's are gay.....

    [​IMG]
     
    Countn'Carbs likes this.
  22. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

  23. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

    ok fellas, got a the 270 today for 300 smackers, does any body know where we can get an adaptor to put a 700 r 4 behind it ? i want to use a 5 speed, but pop says he's to damn old to mash a clutch.
     
  24. OldBuzzard
    Joined: Mar 8, 2008
    Posts: 878

    OldBuzzard

    Buffalo Enterprises. Not cheap. Maybe you should swap that 270 for a 292. The 700R4 will fit right on it.
     
  25. RichFox
    Joined: Dec 3, 2006
    Posts: 10,005

    RichFox
    ALLIANCE MEMBER

    Buffalo Enterprises in Washington makes adapters to bolt up 'Glids, turbo 350 and400 or stickshift blowshields for Chevy V8s. Would the 770 R 4 have the same pattern? 360-652-7684
     
  26. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

    yep. thanks for the info.
     
  27. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

    can you bore a 270 .125 ?
     
  28. motion guru
    Joined: Oct 18, 2009
    Posts: 155

    motion guru
    Member
    from yacolt, wa

    I bored mine 0.125 over. Now at 292 cu in with 9:1 compression - runs like a top!

    [​IMG]
     
  29. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

    that sure is a pretty engine.
     
  30. edweird
    Joined: Jan 4, 2009
    Posts: 3,187

    edweird
    Member

    will early chevy six intakes work on the gmc ?
     

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