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What blower heads for a sbc?

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  • What blower heads for a sbc?

    I need to upgrade the heads for my blown small block. I asked the Edelbrock guys at the shows what they recommend and they have no clue. So do I go for large intake runner and large valve or a medium size runner to keep the velocity up? Should I even worry about velocity with a blower? Right now I get about 8lbs of boost at 6000rpm. The heads are a 1.94 valve stock Chevy head. Price is an object so I need something that will fit my budget also, somewhere in the $1000 range.

  • #2

    Re: What blower heads for a sbc?

    Re: What blower heads for a sbc?

    Without more info on the rest of the combination, you won't likely get much of an answer.

    Engine specs?

    Also, after a recommendation, check ebay, among others for good prices.

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    • #3

      Re: What blower heads for a sbc?

      Re: What blower heads for a sbc?

      Assuming a small-block at 8 psi, you almost can't have too much cylinder head. You're not going to ave any problems with velocity, low-end torque, or throttle response. When you lose those stock heads, watch the boost go down and the power go up.

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      • #4

        Re: What blower heads for a sbc?

        Re: What blower heads for a sbc?

        I'd look at it this way: camshaft duration will determine the max rpm you will run. Head flow needs to be adequate to work at that rpm, with the boost you're running.

        Probably you need the highest flowing heads you can buy with the money you have available.

        My fabulous web page

        "If it don't go, chrome it!" --Stroker McGurk

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        • #5

          Re: What blower heads for a sbc?

          Re: What blower heads for a sbc?

          Without more info on the rest of the combination, you won't likely get much of an answer.

          Engine specs?

          Also, after a recommendation, check ebay, among others for good prices.
          Ok, 355 ci small block, running 8:1 trw turbo pistons, stock rods, Eagle forged crank. Dual rate, small cam in the 460's range for lift if memory serves. I would be guessing at the duration but I remember it was a blower cam so it was a longer duration. BDS 671 blower. 2 750 mechanical Holleys. MSD distributor and 6 BTM spark box running at 16 degrees advance 35 degrees total and all in at 2800 rpm. Weiand intake. Lousy set of Hedman Hedders. 1:5 roller tip rockers on top of those small 1.94 intake valves.
          Muncie M22 4 speed. Dana 60 rear with 4:11's.
          Obviously the cam would go if the new heads were installed.

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          • #6

            Re: What blower heads for a sbc?

            Re: What blower heads for a sbc?

            get some 882's, port them and put in lightweight valve train. best bang for the buck Gen1 SBC head ever.

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            • #7

              Re: What blower heads for a sbc?

              Re: What blower heads for a sbc?

              When your adding boost, just give it big holes to drive the air in!! I always see people talk about head flow for forced induction engines, what the hell does that mean to an engine under boost!??!?! Its almost laughable that knowledgeable engine guys talk about head flow under vacuum when that same head is gonna be used on a boosted application.. I have another approach to working on heads for forced induction combos, but I'm not gonna really get into it.. ;) I use my flow bench in a different manner for forced induction.

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              • #8

                Re: What blower heads for a sbc?

                Re: What blower heads for a sbc?

                flow numbers are based on a pressure differential. Doesn't matter what the absolute pressure is, there's still a pressure differential in a blown engine.

                Good flow numbers n/a are still good flow numbers blown, aren't they? Atmospheric pressure is what forces air into an unblown engine, and that's about 14.7 psi where you live, right?

                My fabulous web page

                "If it don't go, chrome it!" --Stroker McGurk

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                • #9

                  Re: What blower heads for a sbc?

                  Re: What blower heads for a sbc?

                  flow numbers are based on a pressure differential. Doesn't matter what the absolute pressure is, there's still a pressure differential in a blown engine.

                  Good flow numbers n/a are still good flow numbers blown, aren't they? Atmospheric pressure is what forces air into an unblown engine, and that's about 14.7 psi where you live, right?
                  Very astute.... and correct too....... 8)
                  There are very few people in this world who's opinion I value, you are not one of them.

                  300 in 1999

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                  • #10

                    Re: What blower heads for a sbc?

                    Re: What blower heads for a sbc?

                    When you lose those stock heads, watch the boost go down and the power go up.
                    This sounds reasonable to me.
                    Escaped on a technicality.

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                    • #11

                      Re: What blower heads for a sbc?

                      Re: What blower heads for a sbc?

                      flow numbers are based on a pressure differential. Doesn't matter what the absolute pressure is, there's still a pressure differential in a blown engine.

                      Good flow numbers n/a are still good flow numbers blown, aren't they? Atmospheric pressure is what forces air into an unblown engine, and that's about 14.7 psi where you live, right?

                      As I have said in another post, I'm just a silly engine builder that doesn't always go along with conventional thinking.. When an engine is n/a, its its OWN air pump, when its "forced" induction, its not its own air pump anymore, is it?? Is there ANYTHING in this World that exists the same under vacuum as it does under pressure? I feel when air is driven into the engine under pressure, most of the philosophy that exists about air flow under vacuum goes out the window.

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                      • #12

                        Re: What blower heads for a sbc?

                        Re: What blower heads for a sbc?

                        Atmospheric pressure is what forces air into an unblown engine, and that's about 14.7 psi where you live, right?


                        About 11.5psi here :-\
                        Escaped on a technicality.

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                        • #13

                          Re: What blower heads for a sbc?

                          Re: What blower heads for a sbc?

                          As I have said in another post, I'm just a silly engine builder that doesn't always go along with conventional thinking.. When an engine is n/a, its its OWN air pump, when its "forced" induction, its not its own air pump anymore, is it?? Is there ANYTHING in this World that exists the same under vacuum as it does under pressure? I feel when air is driven into the engine under pressure, most of the philosophy that exists about air flow under vacuum goes out the window.
                          Being a silly engine builder that doesn't go along with conventional thinking is great! But it also helps in these discussions if you understand the laws of physics that apply, that way we can all be speaking the same language.

                          We seem to have a communication problem here, probably because I'm talking about absolute pressure, and you're talking about vacuum. The way I see it, there is no such thing as a vacuum, there are only different levels of absolute pressure. If you have a blower making 8 psi boost, that is relative to atmospheric pressure. The absolute pressure in the atmosphere (talking sea level for convenience) is 14.7 psi. Add 8 psi boost to that, you get 22.7 psi. That's the difference between what's forcing air into an unblown engine, and a blown engine.

                          I really don't see why you would consider these to be different situations, requiring different ways of thinking about cylinder heads.

                          I do see why DF would not be so concerned with flow velocity with a carbureted, blown engine...and that's because of the egg beater (blower) that helps to atomize fuel.

                          My fabulous web page

                          "If it don't go, chrome it!" --Stroker McGurk

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                          • #14

                            Re: What blower heads for a sbc?

                            Re: What blower heads for a sbc?

                            The way I see it, there is no such thing as a vacuum, there are only different levels of absolute pressure.
                            Talk to any academic Chemist or Physicist and they'll say the same about Cold. There is no cold only differences in heat.
                            Escaped on a technicality.

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                            • #15

                              Re: What blower heads for a sbc?

                              Re: What blower heads for a sbc?

                              That's right, cold is like dark, and vacuum....it's the lack of the thing you're really talking about, which is heat, light, and pressure.

                              My fabulous web page

                              "If it don't go, chrome it!" --Stroker McGurk

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