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Thread: ported vs non-ported heads on a roots blown combo question

  1. #1

    ported vs non-ported heads on a roots blown combo question

    I currently have a new set of Trick Flow A460 heads that I have not bolted on, standard 10 bolt variety. Question is, should I sell these heads and buy a set of the new 18 bolt variety to support the higher cylinder pressure? Motor is a 528 with a 14-71 blower, not sure on overdrive ration as of yet but will be a race only combo with injection. I've heard that ported heads really don't make alot of difference with a forced induction motor but I want to make sure. If I sell the heads I have I'll have to run the new ones in unported form for now. Thanks in advance! Chris

  2. #2
    Senior Member DYNO OPERATOR
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    Exhast porting can help for sure. I think the difference in if intake porting will be a couple of things. Who does the porting, (Same with exhaust) and the amount of boost necessary for the same power levels. Ported will require less boost for the same power.

    Before I paid to have those heads ported I would know that the person doing them understands and knows that exact head. It has some really thin places under the valves when working the bowl area. Besides that I like to be comfortable with a head if I am doing it, or if it needs expertise beyond my capability I want to know the professional has a through knowledge of what works with that head.

    A side note. If you are going to try to run a stud rocker Trick Flow has just begun making 7/16 Guide Plates for it that you will have to slot the left side hole appx .070 to make it work. Smith Bros has a 7 /16 .165 wall guide plate pushrod. You will need to drill the pushrod holes to a 5/8 size.

    Ed

    Ed
    " Let all things that hath breath, praise the Lord. Praise Ye the Lord" Psalms 150 vs 6.

  3. #3
    Thanks for the response Ed. The heads are already ported and I had them ported by a Ford guy that has done them before, they came out good. I was just considering selling then since they're still new, only to buy a new identical set only with the 18 bolt upgrade. Some are telling me that the 10 bolt heads will hold up fine but I've never built a blower motor before and I want to avoid problems ahead of time. Thanks, Chris

  4. #4
    Administrator RACING JUNKIE bjuice's Avatar
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    i am NO Ed/Curtis when it comes to the head combo's etc...but i am an experienced past alcohol blown injected motor guy..both small block and Big block, have also owned blown carb small block's...

    a pic was posted of one of my past blown alters in the general section under (roadsters)

    Head porting will most definetly help the blower application..Now there are different degree's of blown motors..the street driven small block 144 or big block chevy 177 or street 871/671...At minor levels of boost would not NOT REQUIRE head porting to see the benefits of the forced induction..but even the minor street motors would benefit from a very mild pocket,gasket matched port work...IF ANYTHING LESS HEAT BUILD UP.....i have heard people say PORT WORK is not needed on forced induction but i have learned these are the same people that are too tight to spend the $$ or cannot afford to spend $$ ( which is ok)..or the type of person that never washes their car or changes the oil ( ever)...So please consider the source when you hear comments like that and see what these people have( how their stuff runs) and what have accomplished in the sport.
    ....its also the same people that show up at the track and running 1 second slower than you but for some reason they want to tell you how to tune your car....i deal with that more then you know...LOL

    remember with any blower set up..the quicker you pack it in (air) you must get it out just as Fast if not faster.

    So port work is BIG BONUS and almost a requirment on some higher end blown stuff where HIGH BOOST LEVELS are invloved


    think of it this way...would you like to try to breath thru a "Mcdonald's straw or a 2 inch pipe ?


    This is my KISS theory along with some past experience.

    also depending on your Boost levels..have the blocked O-RINGED AND/ or reciever grooves cut in the heads.....or at minimum get you some FEL-PRO MLS COMETIC head gaskets and be sure to stud the heads and you should be just fine

    thanks

    thanks Brian
    Bjuice..

    "I'M YOUR HUCKLEBERRY ! "

  5. #5
    Senior Member EXPERT BUILDER
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    airflow is airflow, weather naturally aspirated or boosted. Air does not like to turn sharp corners, or have things in its way of flow, so anything you can do to help the air along its path to the cylinder and out again is going to equal hp and torque.
    treat the ports and chambers the same as you would a naturally aspirated motor. A little clean up, port matching, combusion chamber work and a GOOD valve job all done by a reputalble shop that knows what they are doing will be money well spent. You will be suprised at the amount of hp you can lose due to a crappy valve job.... ive been there... 3/10s in the valve job alone.....

  6. #6
    Senior Member RACING JUNKIE
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    Porting is definately the only way to go on a blown motor, smooth the intake runners an match port the intake to the heads. Exhaust is definately where the most power can be gained. Valve pocket porting very important and make sure the headers/zoomies are big enough, i would say 2 1/2" min on a b/blk.

    With a roots supercharger you will definitely be limited by the maximum boost pressure and maximum Rpm the supercharger can be turned. There will be far more to be gained by reducing the total back pressure after the supercharger, and that includes the cylinder head, induction system, intercooler, camshaft and especially the entire exhaust system.

    Anything that causes chronic supercharger constipation is really bad news for airflow, and trying to improve the blower itself is going about it the wrong way.

    Build yourself a traditional high performance engine, but with suitable cam and compression ratio. You will make more Hp on less boost, and much lower thermal sress on everything. Let the whole thing breathe.

    The greatest initial gains are usually made with the exhaust system. There is roughly a 1:1 relationship between boost pressure and total exhaust back pressure. Reduce exhaust back pressure by 4psi, and boost falls by roughly 4psi.

    You then turn the supercharger faster to restore the original boost pressure. Flow increases, power increases, but induction temperatures and the detonation threshold stay about the same.

    just my .02

    Zip.

    I don't know anything about trick flow heads except i have a set of street versions on my Elky.

  7. #7
    Senior Member DYNO OPERATOR
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    I guess we could use an example of what is now Top Fuel and Top Alcoholl heads to answer this.

    You can almost fall inside the intake runners.

    Ed
    " Let all things that hath breath, praise the Lord. Praise Ye the Lord" Psalms 150 vs 6.

  8. #8
    I guess my biggest question is, are my 10 bolt heads going to be okay? They're done, freshly ported and were new out of the box. Block is an Eleminator Ultra that will be O-ringed. Compression is 11.5-1. Cam is a custom Comp, 284/302@.050, .816/.780 lift, 114 lobe angle. Its a race only motor, 14-71 Littlefield with Enderle birdcatcher, not sure on overdrive. What are the best head gaskets to use? Motor is all studs, heads, main, roller cam bearings. Bore is 4.50, 4.15 stroke, 6.8 inch aluminum rod. Thanks, Chris

  9. #9
    Senior Member RACING JUNKIE
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    Quote Originally Posted by ccso640
    I guess my biggest question is, are my 10 bolt heads going to be okay? They're done, freshly ported and were new out of the box. Block is an Eleminator Ultra that will be O-ringed. Compression is 11.5-1. Cam is a custom Comp, 284/302@.050, .816/.780 lift, 114 lobe angle. Its a race only motor, 14-71 Littlefield with Enderle birdcatcher, not sure on overdrive. What are the best head gaskets to use? Motor is all studs, heads, main, roller cam bearings. Bore is 4.50, 4.15 stroke, 6.8 inch aluminum rod. Thanks, Chris
    I use SCE Titans on the s/blk no o'ringed block or heads, they have them built in the gaskets, 1471 littlefield buzzard catcher. Some of the buick guys are running twin turbos with over 30lbs. boost with these gaskets.

    Zip.

  10. #10
    Senior Member DYNO OPERATOR
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    I would say yes.
    Run them.

    Use the 9/16 studs with Cometic gaskets and torque those boogers until you can't pull the wrench. lol. I do them at 145 lbs in four steps.

    With that compression it looks like you will be using alcohol I hope. If you are using alcohol, you may want to think about retarding that cam to not open exhust valves too soon. UNlike with nitrous or Nitro or even blown gas, with alcohol you need to build heat.

    Ed
    " Let all things that hath breath, praise the Lord. Praise Ye the Lord" Psalms 150 vs 6.


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