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MLC - Mid Life Crisis
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Discussion Starter · #1 ·
How much grinding to make a bbc 4.75 crank fit? I have a 4 bolt, gen IV, block that I am looking to stroke the crap out of. Thanks, BK
 

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i'm back!!
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How much grinding to make a bbc 4.75 crank fit? I have a 4 bolt, gen IV, block that I am looking to stroke the crap out of. Thanks, BK

stock gen 4 4 bolt...start with a couple of inches of concrete cause ur gunna hit the h20 jacket before it clears....and probably also smack the cam with a 4 3/4 stroke....4.5 about it for stroke in a stocker and I would sonic check the rail area after ur done hogging it out... oh u could possibly nick the main oil galley 2...if ur set on a 4 3/4 deal start with a aftermarket raised cam block and kind of pointless to run a small bore with that many inches, just go with 4.500 or 4.600 and be done with it.
 

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Amber Racing Services
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4,250 Posts
You can't. There isn't enough room.

You'll grind right into the oil passages right next to the pan rail (where the pan bolts to the block ... there are oil passages that run through the block all the way down the sides).

Sorry, been there ... did it ... ruined a block or two.
 

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steelcomp was here
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You can't. There isn't enough room.

You'll grind right into the oil passages right next to the pan rail (where the pan bolts to the block ... there are oil passages that run through the block all the way down the sides).

Sorry, been there ... did it ... ruined a block or two.
Or two? What, you didn't figure it out on the first one?
Sorry...couldn't resist. :D:)hand
 

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Amber Racing Services
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4,250 Posts
Or two? What, you didn't figure it out on the first one?
Sorry...couldn't resist. :D:)hand
it wasn't a 4.75 crank ... 4.5

and a 4.5 can just barely fit ... but as soon as you've gone too far, you've gone too far.

4.25 is the biggest I would go on a stock block anymore

you know what they say though, you'll never know how far you can go until you try :D
 

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MLC - Mid Life Crisis
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Discussion Starter · #8 ·
Well then I guess my 5.00 crank question doesn't apply...
 

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Administrator
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We fit a 4.375 in a Gen V Bowtie.
Standard deck.

Only cuz Callies had a sale on 1 piece rear seal cranks lol

But it was a late model block and we hacked it up pretty good and rod stroke ratio sucked and tons of mallory from getting the counterweights down far enough to clear.
 
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