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Thread: Heads Help

  1. #1
    Junior Member APPRENTICE
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    Heads Help

    Is it possible to make 325 - 340 HP out of stock 1987 1.94 Intake 1.60 Exhaust heads. They will be sitting on top of a 355 sbc flat top pistons with 4 valve reliefs

    they sell them straight from Chevy dealership or jegs,summit etc...making that kind of hp all day long with those heads....but thats about it on what you described as your motor.

  2. #2
    With enough Nitrous Anything is possible!! :lol:

  3. #3

  4. #4
    Junior Member APPRENTICE
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    No they are not vortec heads they are the old style iron heads and i made a mistake typing the first post they are 1.94 1.50

  5. #5
    Senior Member RACING JUNKIE
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    Like previous posted, a 200 shot of NOS outta get you there.
    If your talking about the later model open chamber heads w/ 1.94 intake valves you'd probably be better off beating a dead horse than wasting any time or money on them, the vortec heads with the smaller combustion chambers and the high velocity ports would suit you much better or you could just save up your money for some better heads all together.
    You can score really good set of aluminum heads now for under $1000
    Goodluck, Charles
    ***IN GOD WE TRUST***

  6. #6
    Senior Member MASTER BUILDER
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    Depends on the cam. A mild bowl blend and 3 angle valve job goes a long way. Are these the Gm swirl port heads? Thats about the era they were from. If so, they are worthless. If its a normal looking port, like a 993, or 186 or something, then that power is achiveable. Just did a 327 resto engine for a 65 Corvette, that was a solid lifter engine, absolutely stick 461 camel backs, with 1.94/1.5 valves, a normal 30-45-60 valve job, and VERY minimal blending under the seat, with a very mild solid cam, he wanted the solid cam, stock rockers, and the only thing added was a Torker 2, because he had it, a new 650 QF vacc carb, and a set of cheap 1 5/8 headers, good machining, balancing, etc, it made 365hp and 385 ft/lbs. THe cam was about quivilent to a mid 220's at .o5o hydraulic, had .465 gross lift, before the lash, so the cam was by no means radical, You can barely hear a lope.

    Frank
    Advanced Performance
    www.get-ap.com

  7. #7
    Junior Member APPRENTICE
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    the cam is a , Hydraulic Flat Tappet, Advertised Duration 300/300, Lift .515/.515,. The GM crate motor 350/290hp uses a set of old style 1.94 1.50 heads and it makes 290hp. Heres the link

    http://www.gmperformanceparts.com/En...P&sku=12499529

  8. #8
    Junior Member APPRENTICE
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    Is this because of the way they are ported

  9. #9
    Senior Member RACING JUNKIE
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    I see no problem getting 325-340hp out of a 350 with basically stock heads.

    GM has been doing it for many many years.

  10. #10
    Senior Member RACING JUNKIE
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    Thing is those are not stock heads they are SMOG heads.
    You could swim in the combustion chambers they are so big ( 76 cc ).
    With flat tops your compression will at best maybe 8.5 to 1 if that high.
    Compression builds power, your gonna want at least 9 to 1 to make any decent power numbers 10.5 to 1 would be better. Look at any muscle car era engine data numbers and the power numbers always went up with the compression.
    Not saying you cant make good power with those heads I.E. bowl blending, port matching, cutting for bigger valves, three angle vavle job etc, etc, etc.
    But for the money doing the above mentioned to some vortec heads ( 64 cc ) would pay off in much bigger dividends. The compression ratio with vortec's and flat tops will be right 10 to 1 which means you'll have to run 03 octane gas but your Hp number just went up significantly no other change will yeild you more power than that. Most junk yards will pratically give them to you and then take them to the machine and for under a couple hundred bucks you have some very good heads.
    But either route your gonna have a decent running 350.
    Hell I've seen people take a bone stock 350 slap a four barrel intake, carb and a small flat tappet cam, cram a 411 out back weld up the spider gears, slicks and WAM BAM they have a drag car and have it run like a rapped ape but with a little more investment, time effort you can really have a barn stormer.
    Goodluck and Happy Thanksgiving, Charles
    ***IN GOD WE TRUST***


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