porting

Discussion in 'Small Block Tech' started by bmxerbrett, Feb 10, 2002.

  1. bmxerbrett

    bmxerbrett Well-Known Member

    If i get the heads ported on my 350 buick how much hp gain should i expect
     
  2. Turbine_guy

    Turbine_guy Member

    This is a good, but loaded question. I'll try to shed a little light on the subject;
    It really depends on the other modifications done to the engine, and the person doing the porting. An excellent article is available in the February 2002 issue of Car Craft, where they describe in detail how to port a set of 360 chrysler heads, and the step by step impact on the engine.
    In your case, it depends how much the engine is being held back by the heads. i.e., if you are running stock exhaust manifolds, lazy compression and cam timing, porting the heads will give a modest boost in power. If the engine is extensively upgraded with intake, cam, compression and exhaust mods, then the effect of good porting will be magnified. One good point is that porting, if done correctly, is "free" power. The engine will only show gains in torque and horsepower throughout the whole rpm range, without tradeoff.
    350's are small bore engines, with high cylinder shrouding effect. Porting must be performed "correctly" to orient the intake flow towards the cylinder center, and vice-versa for the exhaust. Intake to exhaust flow ratio must work in concert with cam timing to optimize the scavenge effect. (One more thing to think about.)
    Are you planning to do the porting yourself, or hire a "professional"? How much time and $$$ are you willing to spend? If you hire someone to do the porting for you, there is a definate turning point where the bang-for-the-buck ratio goes away. If you do the work yourself, how experienced are you?
    Do you have access to a scrap head to practice on, or to cut up, to see how much wall thickness there is in the critical areas?
    I know, I've presented a lot of "ifs", but if you let us know a few more details about your engine, the result of porting can be pinned down better.
    Regards,
    Robin Sipe.

    Ok, I just read your earlier posting, and see you have added a T/A Stg-1 intake, and 600 cfm carb. Jim B. gave good advise, and yes, porting will help quite a bit. If you are going to yank the heads for porting, I would recommend steel shim head gaskets, and a modest cut to the heads to bump the compression. (Short of upsetting the lifter preload.) A cam spec'ed to work with the ported heads, and lower compression will do wonders too.
    A quick pocket port, and nothing else can result in about a 15 hp. boost. Full porting (To work with a good cam, exhaust mods, and a bit more compression) may result in 50+ horsepower. Not bad for a "bit" of grinding & polishing.
    IMO of course.
     
  3. bmxerbrett

    bmxerbrett Well-Known Member

    I was thinking about having a buick porting company do it for me. I have no idea on how to port heads so I'm thinkin i will leave it to the pros on this one. I'm also going to put headers and about 2.5 inch exaust so I will even have more hp. I'm tryin to bring my grandma buick into a camaro killer. it will happen one of these days. Right now i'm saving for fiberglass parts for my car. Front and rear bumpers the rear and front spoiler and even a fiber glasss gs hood. And here is my paint scheme. Black bumbers. Car painted yellow with the black racing stripes. I think that would look way cool.


    How much would a good port and polish job be. Larger valves. Increase the compretion ratio. Blah Blah Blah.
     
  4. GSThunder

    GSThunder Dejavu

    I suggest getting in touch with Jim Burek on the board here(I think his username is Buick535).He did a set of 350 Buick heads for a buddy of mine and did a real sweet job.His 350 engine runs more like a 455 now!:eek2:
     

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