Reworking B1382546 Heads

Discussion in 'Small Block Tech' started by Stevem, May 3, 2022.

  1. Stevem

    Stevem Well-Known Member

    Your welcome!

    Post up some pictures when you get the chance.
     
  2. Stevem

    Stevem Well-Known Member

    Got into the intake ports last night with about 35 minutes of work going into it.

    The work entail boat tailing the guide, tapering in the guide web on the exh valve side of the valve bowl some and also reducing the bowl taper on that side about 1/2” up from the seat to the top of the guide.

    This can be seen in the photos.

    I also ground back the common wall around the head bolt hole, but I mainly did this from half way up that wall to the roof.
    It’s now wider as it approaches the roof and still the stock width at the floor.
    The valve bowl work on the exh valve side took the throat up to 1.66” almost.

    Reworking valve guide on the exh valve side is the hardest work you will do on these on these intake ports!

    Here are the flow results.

    The first column is stock, the second is with the port work and the 3rd is the flow gain over stock.

    .050”. 37.7/////40.8///+4

    .100”. 64.3/////66.6///+2.4
    .150”. 90.8/////95.2///+4.4
    .200”. 121.2/////128.2///+7
    .250”. 152.2/////156.8///+6.6
    .300”. 175.5/////177.9///+2.4
    .350”. 194.5/////198.4///+3.9
    .400”. 207/////214.5///+7.5
    .450”. 211.6/////218///+6.4
    .500”. 218.5/////224.9///+6.4
    .550”. 222.2/////227.2///+5
     

    Attached Files:

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  3. sean Buick 76

    sean Buick 76 Buick Nut

  4. Stevem

    Stevem Well-Known Member

    Hi there folks!
    I had more time to spend on this Mule head this morning so here are the results.
    First note that I am going to show why you can shoot yourself in the foot at times even when you have a flow bench at your disposal like I do, no less if you do not and just go grinding away half cocked so to speak.



    column 1 are the flow numbers where I left off with last time I posted, column 2 is the last rework I did while still using the stock 1.88” valve .
    Column 3 shows the amount of flow loss and flow gain from that rework.

    This rework in test 3 over test 2 shows a loss up to .350” lift of 34.7 cfm in total. and only made for a flow gain above .350” lift of 13.9 cfm in total, so it was not even anywhere near a break even or wash type of deal!

    This also shows why it pays to have a Mule head to make mistakes on!

    column 4 is with a 1,90” valve that has a 11/32” stem ( not a stock 3/8” ) and I redid the valve job to make up for the work I did that killed off the low lift flow.


    note that this 1,90” valve is not a big Tulip shape on the back side like the stock valve is!

    The final test I did was a test with the valve in upside down, but sticking into the valve bowl like the stem would otherwise.

    this test produced only a 1.5% flow gain so the overall port shape right now is very efficient.

    I also did a CC pour on a stock and the ported intake port.
    The stock one came in at 154.3 and the ported one at 165 CCs.
    This shows another good point, which is that with only a 7.5% increase in port volume there is a 10% flow gain taking place.
    This means that no drivability has been lost, in fact it has picked up 2.5%!

    Espcially when you consider that the non Tulip 1,90” valve added like 2 CCs all on its own!

    If you run a .500” lift hydro roller ( about 225 duration @ .050” ) cam with 9.5 comp then the head as it’s now flowing in column 4 should make for a easy 430 hp motor if your intake manifold is not the cork in the system.

    I will post up some photos later.

    CFM @ 28” test pressure.
    .050”. 40.8////36.5////-4.3/////46.2
    .100”. 66.7////59.8////-6.9/////74
    .150”. 95.2////87.8////- 7.4////109.3
    .200”. 128.2////120.4////- 7.8////144
    .250”. 156.7////149.5////- 7.2////168.8
    .300”. 177.9////176.9////- 1/////193.3
    .350”. 198.4////197.4////+-0///213
    .400”. 214.5////218/////+3.5///225.8
    .450”. 218////228.4////+. 10.4///232.6
    500”. 224.9////228.4////+ 3.5
    .550”. 227.2////228.4////+ 1.2
     
    Last edited: Jun 25, 2022
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  5. Dano

    Dano Platinum Level Contributor

    Is 1.90 intake the biggest with the 1.62 exhaust? Any feel yet for your hypothesis that the intake valve size isn't the limiting factor?
     
  6. Stevem

    Stevem Well-Known Member

    Actually I made a mistake with the exh flow info I had posted, the valve I am using is only a 1.565”, but yes I still feel that the size of the exh valve that can be used and how that limits the throat size that the valve bowl can be taken to is the cork.

    With the amount of short turn height the exh ports have you would need to max out the throat size to 92%.

    Doing such would certainly pick up the high lift flow numbers once the short turn was widen, but below .350” lift it would devastate the flow numbers.

    in terms of where I have this intake port flowing now with the 1,90” 11/32” stem valve I could likely go for more peak flow and get up to 240 cfm, but it would come at the expense of low lift numbers.
    The 144 cfm that I have taking place at .200” lift is a nice fat number and is critical when you have a good scavenging tuned exh system to making high VE numbers during the overlap period.
    The large depression created by the exh system above let’s say 4500 rpm starts the intake flow moving into the cylinders well before the piston even starts on its way down the bore !

    In a well set up race motor the depression created in the cylinder by a tuned exh system is greater then the depression ( 28” H2O ) that we use when doing flow testing work.
    Think about that for a few seconds!
     
    Last edited: Jun 25, 2022
  7. Max Damage

    Max Damage I'm working on it!

    I only understand about 25% of this, but it's super interesting and cool. Thanks for sharing all this knowledge and information...

    In post #26 above, when you refer to depression, I suspect you mean depressurization?
     
  8. Mart

    Mart Gold level member

    Steve, how do these flow #'s with 3/8 stems compare?
     

    Attached Files:

  9. Stevem

    Stevem Well-Known Member

    Max, you can think of it as vacuum.

    Mart, the intake flow numbers make sense to me, but the exh numbers do not.

    For instance if you take your peak intake flow percentage of 90.5 and Times it by the corrected flow numbers for that number 4 test range of 267 you end up with 241.6 cfm, so it’s in the ball park with my numbers at least in terms of peak flow even though yours have to lift to .600” to my .450” lift.

    I also do not understand that big correction factor of 10%. iE 267/295, but I guess it’s possible if it was a very hot and humid day.
     
    Last edited: Jun 25, 2022
  10. Mart

    Mart Gold level member

    Steve, those are Kevin (storm1) heads done by a performance shop around the corner from me. He does V6 turbo stuff.
    Mine flow much less than his.
    I looked at that port work when Kevin picked them up and thought they were pretty slick.
    Seems all benches have some variables on flow #'s with the particular tube/extension lengths, bore size pipe, etc, being used.
    Hey, just carry on with getting stellar flow results with these problem 350 iron heads. :)
    Be interesting to see the end result.
    Sean has a guy doing some irons & TA heads also. If there's a magic bullet, one of you guys will find it.
     
  11. Stevem

    Stevem Well-Known Member

    Thanks for the kind words!
    For now this is where I am leaving off with these heads since they will more then make the power this fellow is looking for.
    I now need to get 8 custom 1,90” valves made.

    After I finish these I have a set of Ford 390 heads to do, and then maybe for fun I will go back to this SBB Mule head and put in a 1.92” valve and port it for all its worth.
     
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  12. sean Buick 76

    sean Buick 76 Buick Nut

    Awesome! FYI here are a bunch more flow numbers in this thread here. Both iron and alum 350 heads.

    https://www.v8buick.com/index.php?t...d-flow-sheets-here.352425/page-3#post-3315645
     
  13. Stevem

    Stevem Well-Known Member

    Here are some photos of the work done to get the level of flow where I am at.
    Note that I am starting to think that my mule head I am using has had a valve job done during the course of its life which is why I am seeing 3 angle cuts, valve spring shims and with the numbers folks have been posting a higher level of off the bat flow then what I believed to be stock.
    On what I have been calling a stock intake port the diameter of the valve bowl right at the end of the valve job bottom cut is 1.690” on average, my valve job has taken this up to 1.735” or so.
    Here are some photos.

    The photo with the 1.60” template is a stock int port, and that template is just hanging there by a thread so to speak.
    The next photo is that same stock port and the template is down as deep as it will go.
    Note that it is still 3/8” above testing on the top of the valve guide.
    The next shot is a 1.66” set in the ported valve bowl, and this also is hanging on for dear life so the average diameter of the valve bowl might be more like 1.67”.
    The next shot is that same 1.66” template down in bowl such that it’s sitting right on top of the valve guide.
    Remember that when you look at these two last photos that I am now using a 1,900” valve.
     

    Attached Files:

  14. Stevem

    Stevem Well-Known Member

    Hi all.
    Here latest and last intake flow numbers I will post about these heads because this is where I am stopping porting work on them.

    yesterday I spent 1.5 hours velocity probing these intake ports, and this morning I spent one hour more doing the same at all different lift points.

    To recap I have a 1.90” 11/32” stem valve in this head that does not have a under cut stem, I did add a nice wide 30 degree back cut to the valve which took the main 45 seat down to .055” wide from .100”

    Here are the new flow / final flow numbers and the cfm gain over stock..
    .050”. 52.5/////14.5

    .100”. 85.6//////21

    .150”. 119.5/////28.7

    .200”. 154.5/////33.3

    .250”. 178.6/////26.4

    .300”. 201.5./////26

    .350”. 224.4/////29.9

    .400”. 235.7/////28.7

    This port is moving so much air that the change over point is taking place at only .150” lift where as with this size valve and port area that would be taking place at a tad over .350” lift.
     
    Last edited: Sep 18, 2022
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  15. Mart

    Mart Gold level member

    .500 to .600 lift #'s?
     
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  16. Stevem

    Stevem Well-Known Member

    No, the intake flow numbers peaked right there at .400” lift so that’s where I stopped the flow test.
     
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  17. Mart

    Mart Gold level member

    So you're saying flow went dead & leveled/ maxed out at .400 lift and 236 cfm?
     
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  18. Stevem

    Stevem Well-Known Member

    Why are you so stuck on using the term "went dead"?
    The flow just peaked at .400" lift, just like the stock port did at .550" lift once it hit 222 cfm.

    Once again let me say that there is no harm in running way more lift then .400" with a head reworked this way, just like there is no harm in doing the same with the stock head above peak flow levels, as long as with either head no major reduction of air flow numbers is seen taking place as the valve lift increases.
     
    Last edited: Sep 19, 2022
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  19. Stevem

    Stevem Well-Known Member

    Well it’s raining here and can’t get the lawn mowed and the set of heads I am working on is waiting on valves, this all means I had time to pull the 350 mule head off the shelf and do some tweaking.

    Here’s the flow numbers once again where I left off and the new final ones since I see no future potential in these without welding or in the least epoxy getting put in.

    details

    1,90” valve .
    11/32” stem and no neck down.
    Valve back cut with a 30.
    Throat 87.5% of 1.90”
    Flow@28”

    first column is where I left off, second is todays numbers .
    I spent another 30 minutes on the port which includes tweaking the valve job.

    No polish was done anywhere and with the 100% humidity due to the rain these numbers are likely 2 cfm down from what would be had with 40% humidity.

    .050” ,,,,53.5,,,,69.7
    .100”,,,,85.6,,,,87.3
    .150”,,,,119.5,,,,120.4
    .200”,,,,154.5,,,,152
    .250”,,,,178.6,,,,176.7
    .300”,,,,201.5,,,,201.5
    .350”,,,,224.4,,,,223.8
    .400”,,,,225.7,,,,243.9
    .450”,,,,232.6,,,,246.9
     
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  20. Mart

    Mart Gold level member

    A friend that works/ports at Livernois Motorsports told me the same thing when he looked my ported irons over....
    Greg Gessler had an epoxied set of "wild 350 iron heads" pictured on his website.
     

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