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How much stroke will stock HEMI block accept?
#1530056
11/08/13 11:27 AM
11/08/13 11:27 AM
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Joined: May 2012
Posts: 55
Carroll, IA
jercars
OP
member
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OP
member
Joined: May 2012
Posts: 55
Carroll, IA
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Thinking of putting some bigger guts in my hemi looking for some times. Factory block casted in 1973 bored .030. I'd like to stick with that bore since the holes are in perfect condition. How much stroke can I throw at this thing without getting into clearance issues. A Little grinding doesn't bother me but I don't want to go crazy on it since it's just a street car.
Last edited by jercars; 11/08/13 02:52 PM.
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Re: How much stroke will stock HEMI block accept?
[Re: jercars]
#1530057
11/08/13 11:44 AM
11/08/13 11:44 AM
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Joined: Nov 2003
Posts: 5,160
Texas
dannysbee
master
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master
Joined: Nov 2003
Posts: 5,160
Texas
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If you want to stay with the internal oil pickup 4.25 with the Chevy rod size is a good fit. If you go to a external pickup I know the 4.5 will work. Anything larger I am not sure of.
Getting old just means you were smarter than some and luckier than others.
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Re: How much stroke will stock HEMI block accept?
[Re: jercars]
#1530058
11/08/13 12:04 PM
11/08/13 12:04 PM
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Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
B G Racing
master
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master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
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Quote:
Thinking of putting some bigger guts in my hemi looking for some times. Factory block casted in 1973 bored .030. I'd like to stick with that bore since the holes are in perfect condition. How much stroke can I throw at this thing without getting into clearance issues. A Little grinding doesn't bother me but I don't want to go crazy on it since it's just a street car. Also the motor came with a Comp Thumpr cam and I have zero experience with that series. I don't have the specs with me but I think lift was around .500 and .525 and duration was around 305°. Anyone ever tried one?
With 2.200 Chevy pin,large bore clearences and external oiling you can go up to a 4.750 but with a .030 bore I would suggest you keep the stroke to 4.500 or less.A 4.500 stroke and 4.310 bore will net you aprox.526" at 4.270 a little less.Ideally for street 4.150 at your bore will net you just under 500" and make a great street/strip engine.We usually see those 471" to 484" engines make power equal to the 500". 
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Re: How much stroke will stock HEMI block accept?
[Re: Cab_Burge]
#1530062
03/05/14 06:02 PM
03/05/14 06:02 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
master
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master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
would be a 4.25 stroke with BB Chevy rod sizes and use a decent set of 7.100 long BB Chevy type H beam rods with the .990 BB chevy wrist pin sizes also
that's my setup, but i have a mopar siamese block, so don't' think that counts as stock.
didn't have to modify anything, and using the stock internal pickup.
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Re: How much stroke will stock HEMI block accept?
[Re: Cab_Burge]
#1530063
03/05/14 06:22 PM
03/05/14 06:22 PM
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Joined: Feb 2014
Posts: 655
Huntsville, AL
Airwoofer
mopar
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mopar
Joined: Feb 2014
Posts: 655
Huntsville, AL
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Quote:
I have built several different sizes of Street Hemi with 3.90 stroke to 4.375 stroke. My favorite would be (if I owned a Hemi now, which I don't anymore  ) would be a 4.25 stroke with BB Chevy rod sizes and use a decent set of 7.100 long BB Chevy type H beam rods with the .990 BB chevy wrist pin sizes also That may require a custom piston instead of a shelf piston but it will ne worth the additional costs of that piston. If it is a iron headed pump gas street motor keep the compression under 10.5 to 1  It should really set you way back in the seat at WOT once it hooks the smoking tires up  
You just described my 540 except I have alum heads and more compression (will drop it next time). The rod ratio with that 7.1 rod should help the side loading. Also, with a 4.25 stroke you can use a Milodon windage tray.
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