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  •  » GT40p heads and Howards cam vs push rod length

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    8/20/2023 11:45 AM  #1

    BILLY WALTON from GEORGIA
    Carrollton, GA Bash Host

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    From: CARROLLTON GEORGIA
    Registered: 4/14/2013
    Posts: 2,431

    GT40p heads and Howards cam vs push rod length

    When my engine was built they put the GT40p heads with Comp Cams 26986 valve springs and PRW pedestal mount 1.6 roller rockers. the Cam is a Howards 221275-12 . they put stock push rods back in with all that should it have had differnt length pushrods??

    Last edited by BILLY WALTON from GEORGIA (8/20/2023 11:48 AM)

    Its really me....I fixed my caps lock .
     

    8/20/2023 11:53 AM  #2

    TKOPerformance
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    From: Newark, DE
    Registered: 12/15/2014
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    Re: GT40p heads and Howards cam vs push rod length

    Impossible to say.  You'd need to measure and check the pattern on the top of the valve stem.  If they did all that then its fine.

     

    8/20/2023 11:55 AM  #3

    Quicksilver
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    From: California Central Coast
    Registered: 9/22/2013
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    Re: GT40p heads and Howards cam vs push rod length

    The machine shop you used had a special push rod they should have used to get the correct  length push rod for your engine. You could ask them, Butt I don't think you have anything to worry about. I would think an obvious problem would of shown up by now.

    Money can't buy happiness. Butt it can buy Car Parts... and that is pretty much the same thing.67 FastBack
     

    8/20/2023 12:08 PM  #4

    BILLY WALTON from GEORGIA
    Carrollton, GA Bash Host

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    From: CARROLLTON GEORGIA
    Registered: 4/14/2013
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    Re: GT40p heads and Howards cam vs push rod length

    I just dont feel like its running right seems to be under powered for all thats in it to me of course it still has the 3.00 gear rear with the 5 speed....3.55.1 is on the way ....I just really feel like something just aint right somewhere. thought about the timing chain being advanced or retarded or something. I figured I would get the rear gears in before I messed with it to much. Was just curious if it should have had differnt length push rods with that cam and stuff.

    Its really me....I fixed my caps lock .
       •Thread Starter
     

    8/20/2023 12:14 PM  #5

    Greg B
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    Registered: 4/01/2013
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    Re: GT40p heads and Howards cam vs push rod length

    The push rod should still be the same 6.325.   More of an issue is hopefully whoever built it understands checking lifter preload and how to use shims on pedastal rockers. 

    For me, that is definitely best done with lifters bled down, cam on base circle, and intake manifold off.   My mind couldn't do it any other way.

    Last edited by Greg B (8/20/2023 12:15 PM)

    If multiple things can go wrong, the one that will go wrong will be the one that causes the most damage.
     

    8/20/2023 12:23 PM  #6

    BILLY WALTON from GEORGIA
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    From: CARROLLTON GEORGIA
    Registered: 4/14/2013
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    Re: GT40p heads and Howards cam vs push rod length

    I am positive the intake was not off when the rockers were added another shop added them trying to get it ot run right I have had nothing but problems nobody seems to work on the the older engines like this anymore. I have a friend that use to run the local SVT shop at the local Ford I need to get it to him I am sure he could get it all fixed up. I am beginning to wish I had just rebuilt the 289 that was in it and left the roller world alone.

    Its really me....I fixed my caps lock .
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    8/20/2023 12:50 PM  #7

    6sally6
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    From: Surfside Beach,SC
    Registered: 4/02/2013
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    Re: GT40p heads and Howards cam vs push rod length

    Swing by the shop that installed the push rods and tell them your concerns......
    kinda like this


    https://youtube.com/clip/UgkxdmyBYp9FSo1CZRyDGTBZcJBFwa0zYypn?si=8evkVwaSdLpTjwEq


    I axe almost everybody this question BILLY who grumble about not having the "umpph" they think their engine should have..........

    Did anybody adjust/tune your ignition advance curve in the distrib.?
    Total advance of 36* @ 2000 RPM.
    (Don't 'even' worry what the initial advance is...its the TOTAL advance that's important and having it all in by 2000RPM).
    With the cam....headers....and 4 barrel carb you have installed.....you should be mumbling to yourself when you stab the accelerator. Even with the 300:1 gear. ESPECIALLY when you nail-it in 1st & 2nd gear !

    Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
     

    8/20/2023 2:04 PM  #8

    Nos681
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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
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    Re: GT40p heads and Howards cam vs push rod length

    Sounds like you may have some tuning to do Billy.

    Different engine may require different tuning.

    Get some bad gas?
    Check for vacuum leaks?

     

    8/20/2023 4:54 PM  #9

    TKOPerformance
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    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,463

    Re: GT40p heads and Howards cam vs push rod length

    One thing I always do is verify that TDC on the balancer is actually TDC.  Ford used 3-4 different locations for timing over the years.  You get the wrong balancer and pointer combination and you could be 40-60 degrees off timing wise.  Yes, hard to believe but it probably will still run like that. 

    On the timing set, anything is possible, but if the cam were say retarded it would lack low end and make a lot of top end power.  Monkeying with cam tining doesn't really add power, it just moves around what you've already got. 

    I'd verify TDC then check ignition timing.  IME a proper advance curve makes a night and day difference.  I'd do that first them check the jetting in the carb. 
     

     

    8/20/2023 6:11 PM  #10

    Nos681
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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
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    Re: GT40p heads and Howards cam vs push rod length

    On top of what TKO mentioned, I would find out if the timing set used with new camshaft is correct as well.

    As some factory timing sets have retarded timing built into them.

     

     

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