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Author
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Topic: rod piston question.
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Pure Stang
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Member # 7251
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posted
 
 
trying to learn a little something. can you just install a 5.400 (i think need to double check) rod and a 30 over bore piston to a stock block just boring the block? or does crank need to be changed? what is stock length? if it works with a stock crank what will be the ci? thanks peeps
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HEART BREAKER
R.I.P Willie Guzman (5ltrsvt) you will be missed brother.
04/24/87 - 11/23/2012
90 lx 347 RIP
86 gt
89 lx- next project
Posts: 6497 | From: San Jose | Registered: Nov 2006
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wilit
Mustang Messiah
Member # 3367
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posted
5.090" is the stock 302 rod length. Boring the block will not affect anything with the rod length/ratio. The 289 used a 5.155" rod and most stroker kits use a 5.400" rod, though some Probe kits use a 5.315" rod to move the ring lands up out of the wrist pin area.
If you're using a stock 302 crank, you need a 5.090" rod. Boring the block .030 over will get you 306 cubic inches with a stock 302 crank.
[ May 26, 2011, 01:08 AM: Message edited by: wilit ]
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"If a man hasn't found something worth dying for, he isn't fit to live." - Martin Luther King Jr.
Posts: 4793 | From: 37.78514° North 122.40100° West | Registered: Oct 2003
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Pure Stang
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Member # 7251
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posted
Cool thanks.
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HEART BREAKER
R.I.P Willie Guzman (5ltrsvt) you will be missed brother.
04/24/87 - 11/23/2012
90 lx 347 RIP
86 gt
89 lx- next project
Posts: 6497 | From: San Jose | Registered: Nov 2006
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93PONY
Mr. Valve Events
Member # 60
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posted
You can get .030" overbore pistons for a 5.400" rod and 3" crank. It's what they call a long rod 306.
The longer the rod, the shorter the compression height of the piston in order to run in the same deck height.
Compression height = distance from wrist pin to top of piston.
Deck height = 1/2 stroke + rod length + compression height
IE 8.2" = 1.5 + 5.09 + compression height
or
8.2" = 1.5 + 5.4 + compression height
Work the formula for compression height and find pistons with the correct bore and compression height. Hint: Probe makes them.
Remember to check the rod specs as well. .927" pin bore in the piston will not work with a rod that has a .912" pin bore. Same goes for the big end. Some 5.4" rods are setup for a SBC rod journal size instead of a Ford journal size. The crankshaft can always be ground down to SBC size....and you can off-set grind the crank for more stroke.
That's how I got a 3.10" stroke out of a stock 5.0 crankshaft. I had the journals ground down to SBC size (2.0") and offset to increase the stroke. 5.4" rods and custom pistons (using formula above to figure out compression height) and I had a mild Stroker. You can also offset grind for less stroke, or go down to a Honda Journal size!
[ May 26, 2011, 10:50 AM: Message edited by: 93PONY ]
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www.advancedenginedevelopment.com
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Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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turbo50
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Member # 6700
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posted
Shaun is correct, however, he either does, owns or knows someone with a machine shop lol
That stuff adds up at a machine shop, as do the pistons.
I think you could stroker kit it and call it real if you dont already have ur parts.
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Posts: 7606 | From: Discovery Bay, California | Registered: Apr 2006
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Pure Stang
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Member # 7251
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posted
I have the pistons and rods. Had them in my garage already. Just spare parts just trying to figure out what to do with them. Forged pistons and h beam rods.
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HEART BREAKER
R.I.P Willie Guzman (5ltrsvt) you will be missed brother.
04/24/87 - 11/23/2012
90 lx 347 RIP
86 gt
89 lx- next project
Posts: 6497 | From: San Jose | Registered: Nov 2006
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triple b
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Member # 8763
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posted
I cant remember where i saw it but if google long rod 306 you can find the piston you need to make that work. I think its a chevy 327 piston not 100% sure tho.
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2004 tahoe
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Posts: 1730 | From: sacramento ca | Registered: Nov 2008
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