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4.25" stroked B motor #536699
11/25/09 08:35 PM
11/25/09 08:35 PM
Joined: Oct 2009
Posts: 276
Temecula, Ca.
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zzyzxpat Offline OP
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zzyzxpat  Offline OP
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Joined: Oct 2009
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Temecula, Ca.
I was interested to hear opinions on stroking a B motor to 4.25". What kind of wear does this put on cylinder walls. This would be a street motor run under 5500rpms. Thanks, Pat


" The last official act of any goverment, is to loot the treasury" George Washington
Re: 4.25" stroked B motor [Re: zzyzxpat] #536700
11/25/09 09:32 PM
11/25/09 09:32 PM
Joined: Jan 2003
Posts: 30,947
Oregon
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AndyF Offline
I Win
AndyF  Offline
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Posts: 30,947
Oregon
Basically gives you a setup similiar to factory 454 Chevy motors. Should last a long time if you use good parts and the machining is proper.

Re: 4.25" stroked B motor [Re: zzyzxpat] #536701
11/26/09 02:12 AM
11/26/09 02:12 AM
Joined: May 2008
Posts: 5,399
Aurora, Colorado
451Mopar Offline
master
451Mopar  Offline
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Joined: May 2008
Posts: 5,399
Aurora, Colorado
It should run fine with the lower rpm use. The only issue may be running the stock internal oil pickup? Depending on the rods and rod journal size you may have to use an external oil pickup, it will all depend on how much clearance the crank/rods needs around the oil pickup boss in the block.

Re: 4.25" stroked B motor [Re: 451Mopar] #536702
11/26/09 02:54 AM
11/26/09 02:54 AM
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
dodgeboy11 Offline
super stock
dodgeboy11  Offline
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Posts: 1,025
Las Vegas, NV
It can be done, even with the 1/2" pickup tube. I managed to get one to fit in a 440 with a 4.375" stroke. Had to pinch the tube a bit for clearance, but it did, indeed, clear.
The 496 383 runs real good for the record.

Re: 4.25" stroked B motor [Re: zzyzxpat] #536703
11/26/09 03:22 AM
11/26/09 03:22 AM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Cab_Burge Offline
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Cab_Burge  Offline
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Posts: 43,007
Bend,OR USA
I built a 4.25 stroke B motor in a 1972 400 block back in 2002, I used a Ohio Crankshaft Company crank with the mains turn down to fit the B motor mains and BB Chevy 2.200 rod journal size I used a set of CAT BB Chevy 6.8 long H beam rods and a custom Ross piston with a 22 CC dish which made the compression ratio 9.25 to 1. I bought a Comp Cams custom (not ground for my motor, someone else had it made and sold it to me ) ground solid roller camshaft and a set of ported 906 heads with 2.14 intake valves and 1.81 exhaust valves. That was before Edelbrock had came out with thier aluminum performer heads for the B-RB motors I used a Eddy low deck six pack intake and a set of Holley vacume carbs on the motor, it made 612 HP at 5600 RPM and 644 Ft. lbs torque at 4500 RPM on CA pump gas on Vibrancic Bros dyno in Ontario, CA I was really hoping it would make between 550 and 575 HP at 6000 RPM, Boy was I glad with those results If I was to do it over, which I will I have several 400 blocks left and the original crankshaft which I will use a 6.700 long rod this time and a different set of heads, 440-1 CNC ported by MCH I ended up swapping the heads on the original motor to a set of Eddy RPM heads that I had MCH CNC port and I also switch cranksafts to a 4.300 stroke crank to move the pistons up .025 to increase the compression with the aluminum heads to 10.29 to 1. Those two changes made the car go over two tenths faster(10:69 to 10:43) and almost 4 mph faster(124.2 to 128.62) I have also made several other stroker wedge motors(3.91 stroke 440, 4.25 stroke 426 wedges and hemi and several 4.25 stroke wedges and hemi and my 4.300 stroke 400 block and the latest one is a 440 block with a 4.375 stroke crank with a set of Indy SR M.W. port heads), all of them run well


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: 4.25" stroked B motor [Re: Cab_Burge] #536704
11/26/09 10:18 AM
11/26/09 10:18 AM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert Offline
Circle Track
Happy Birthday RapidRobert  Offline
Circle Track

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
when mixing/matching stroke/rod lengths whats the shortest CH piston you can go with for a long life street eng?


live every 24 hour block of time like it's your last day on earth
Re: 4.25" stroked B motor [Re: zzyzxpat] #536705
11/26/09 10:22 AM
11/26/09 10:22 AM
Joined: Oct 2009
Posts: 276
Temecula, Ca.
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zzyzxpat Offline OP
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zzyzxpat  Offline OP
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Temecula, Ca.
Thanks for the responses. I am basically trying to get my ducks in a row here. I have a all original 66 coronet, 361. This was a barn car that sat for 28 years and I am in the process of putting it back together. I know the smart thing would be to go 440, but I want to keep it all original, yet be a monster. My plan is to use the 440 source 4.250 crank and rods. Pistons have to be made anyway, so build it with about a .035 quench at about 10.0-1, with a Voodo cam and Eddy manifold. The heads are 516s which are ready with 1.7 exhaust valves This will be a little more expensive, but it will be something a little different. Thanks again, Pat


" The last official act of any goverment, is to loot the treasury" George Washington






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