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Author
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Topic: stock 289 pushrod length?
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mustangboy
Gearhead Posts: 1343
From: Ont, Canada
Registered: Mar 2002
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posted 06-17-2005 10:45 PM
 
I'm rebuilding what was a totally stock 1966 289.I ordered new pushrods from comp cams and they gave me a set of high energy 7831-16 which are supposed to be stock replacements for 65 and up small blocks.I compared them to my stockers and they are visibly longer,close to an 1/8th of an inch on a ruler.The Tom Monroe book lists early pre-69 small blocks pushrods at 6.825 and the comp cams pushrods are 6.876. or .051 longer.Also my stock valves were reused and had the ends resurfaced just enough to clean them up(about .020).Does anyone make stock length pushrods for 289s? Can I run the longer pushrods ok?I am also using the comp cams self aligning roller tipped magnum rockers to prevent valve tip wear.------------------
1968 mustang j-code sprint.13.69@101 306cu.in, stock ported heads,weiand exellerator,650 holley DP,hedman hedders,comp 292 Magnum cam,4-speed,8 inch 4.11 detroit locker ....66 mustang coupe project.289 4 speed,3.20 rear http://mustangsandmore.50megs.com/MembersPics/mustangboy.html
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68 Coop
Gearhead Posts: 5847
From: Mesquite, NV. 89027
Registered: Oct 2004
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posted 06-17-2005 11:15 PM
Looking at the NPD book, it says the length is 6.809" for 66-68 exc Hi-Po.------------------
William
68 Coupe
"Restomod in Progress"
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mustangboy
Gearhead Posts: 1343
From: Ont, Canada
Registered: Mar 2002
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posted 06-18-2005 01:09 AM
I just tried running the valves through one cycle with the tips covered with black magic marker.With the longer pushrod the marks were about a millimeter off centre towards the exhaust side of the head.The stock 289 pushrod had it dead centre.It looks pretty well exactly like this article where in the first example they check it and then recheck with a .050 shorter rod http://circletrack.com/techarticles/4635/ How critical is this in a mild street engine?(PS when clicking on these pics to enlarge you must close them or it will keep showing the same picture)------------------
1968 mustang j-code sprint.13.69@101 306cu.in, stock ported heads,weiand exellerator,650 holley DP,hedman hedders,comp 292 Magnum cam,4-speed,8 inch 4.11 detroit locker ....66 mustang coupe project.289 4 speed,3.20 rear http://mustangsandmore.50megs.com/MembersPics/mustangboy.html [This message has been edited by mustangboy (edited 06-18-2005).]
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mustangboy
Gearhead Posts: 1343
From: Ont, Canada
Registered: Mar 2002
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posted 06-18-2005 11:10 AM
I've been doing some digging and found some strange stuff.Comp cams "high energy" series pushrods are 6.876 long yet their "magnum series" which is a step up in strength is 6.800 for the same application  I checked out Crane and they seem to acknowledge that Ford had a couple of different size pushrods back then.They list 1963-68 as 6.804 and 69-86 as having 6.876 which sounds correct to me.
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Moneymaker
Administrator Posts: 29200
From: Lyons, IL, USA
Registered: May 99
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posted 06-18-2005 11:46 AM
As long as the rocker arm tip is still close to the center of the valve, you are OK.
The longer push rod will actually give you some more lift in the low lift range of the cam lobe travel.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,'04 &'05
First NHRA & IHRA 289 automatic Superstock Mustang in the TENS 06-99
First SS/MA in the TENS 04-03
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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