350 tbi head cc's

Discussion in 'Engine Topic' started by MartinD, Feb 27, 2006.

  1. MartinD

    MartinD Veteran Member

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    i have a set of the 193 tbi heads and am hearing two different cc's 64 and 76.they are 1991 model heads.im going to flat tops on this tbi motor and dont want to mess up with 10to 1 compression if they are 64.i think that motor was around 8.5 to 1 with the dish pistons so that would make them around 76 wouldnt it?
     
  2. HULKZ28

    HULKZ28 Veteran Member

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    I believe those are swirl port heads used on 305s and 350s. I dont know the ccs on the chambers but iv read that they make good torque and dont flow very well at high RPMs. The intake port measures 180ccs.what for someone to back me up on this but im pretty sure. I have a pair kickin around here somewhere.Also check mortec.com or chevy tech.com.. watch your cam choice and comp. level with these heads. good luck.
     
  3. Kamikaze

    Kamikaze Veteran Member Lifetime Gold Member

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    You can port the crap outta those heads but they would still fall flat on their face after 4000 rpm! Lift is tough too as these have similar valve guide problems to the early Vortec heads. I've seen some go only up to .450" lift and a few that can go as much as .480" lift but any cam running that high will get choked up by the restrictive flow.

    The intake port was like a cast-in corkscrew. This was an attempt to induce high swirl and it did work for heavy cars and the trucks but torque was it's key result. The exhaust wasn't too bad but even if you did port them they'll nearly move more air out than what the intakes put in the cylinders.

    You could run flat-tops with these heads but don't push compression beyond 9.75 to 1 unless you are running a long duration 220+ cam @ 050 with a dual pattern. Be careful decking these heads and make sure to run a composite gasket with about 0.040 compressed thickness.

    If you were to build a low rpm motor for a daily driven vehicle, they will work fine but remember they take the late style intake pattern where the middle bolts are vertical and not angled with the intake flange.

    If you are running a TBI, the best manifold is the Edelbrock TBI with the torque tube inserts below the throttle body. These sit into the manifold and is not a spacer. You could add the Trans-Dapt Swirl Torque spacer and do some minor TBI mods like the injector spacer, adjustable pressure regulator and flow matched injectors but all this will not run to it's full abilities without a good re-programmed E-Prom.

    One other thing, long tube headers will work with this but shorties or Tri-Y's seem to work better with this combo and a good high flow 3" cat and a good preformance single inlet muffler with your choice of outlets.

    We've done many sport trucks with these mods and some Caprices, and Camaros and they work well.
     
  4. Damon

    Damon Veteran Member

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    The little LO3 305 TBI motor (used in many late 80s passenger cars) used the #187 heads which had smaller 58cc chambers and smaller 1.84/1.50 valves. FLow was miserable on both sides out of the box. I measured max valve lift on a set I swiped off a 92 305 TBI motor and the retainer hit the guide seal at only .440" lift! The stock TBI engies these heads were used on had very little lift- not even over .400" so I guess they never built the head to handle much lift. Compression was 9.3:1 with slightly dished pistons.

    The slightly less pathetic LO5 350 TBI motor (trucks) used the #193 heads you have. They had slightly larger 64cc chambers and slightly larger 1.94/1.50 valves but weren't really a whole lot better than the 305 heads, above. Compression was 9.3:1 with -12cc dished pistons and a fairly thin head gasket. If you use typical 4 eyebrow flattops and a GMPP .028" composite head gasket you'll be arouind 9.75:1
     

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