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Discussion Starter #1
how big can 281's be bored out to?
 

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460!
 

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Discussion Starter #6
boring and stroking
 

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Discussion Starter #11
can i safely bore and stroke a 281 to 302 cubic inches?
 

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can i safely bore and stroke a 281 to 302 cubic inches?
302 is 4.9L, so yes.

And for all you bastards that are gonna come out of the woodwork, 302 cubic inches is 4.94889333 liters. 4.94. If you don't believe me, do the math yourself, 1 liter is 61.0237 cubic inches.
 

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5.8 is the biggest I've seen if you use MMR's big bore sleaved block. I hear Paschal Performance makes a 6.2l sleaved modular motor but I haven't found any info yet.

NEW MMR 351R CAST IRON BLOCK
The Biggest Baddest Modular EVER, sporting 351 cubic inches/5.8 Liters with a factory stroke 5.4 Crankshaft, 360 degree cooling around cylinder heads eliminates hot spots and reduces detonation. ALL factory components bolt right on, accepts all heads (2V, 3V, and 4V)

 

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5.8 is the biggest I've seen if you use MMR's big bore sleaved block. I hear Paschal Performance makes a 6.2l sleaved modular motor but I haven't found any info yet.

NEW MMR 351R CAST IRON BLOCK
The Biggest Baddest Modular EVER, sporting 351 cubic inches/5.8 Liters with a factory stroke 5.4 Crankshaft, 360 degree cooling around cylinder heads eliminates hot spots and reduces detonation. ALL factory components bolt right on, accepts all heads (2V, 3V, and 4V)

:drool must have..............
 

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A 281 ci (4.6L) motor has a stock bore of approximately 3.552" and a stock stroke of 3.54". It can be safely bored to about 285 ci (.030" over) without sleeves. With sleeves it can be bored to a maximum of approximately 3.7" (about .25" over). With the stock stroke that will take it to approximately 305 ci (5.0L). The cylinders cannot be bored to 4.0". You can get a stroker 3.75" crank that will increased the sleeved motor to 323 ci. The 351 above is based on the 5.4 motor not the 4.6.

(Note: To calculate cubic inches divide the bore by 2 to get the radius. Multiply the radius times itself then times 3.14 (pi) then times 3.55 (stroke) then times 8 (cylinders).)

Ford has a modular Boss block that has a 3.7" bore without sleeves. And the new Raptor modular motor has a 4.0" bore.
 

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302 is 4.9L, so yes.

And for all you bastards that are gonna come out of the woodwork, 302 cubic inches is 4.94889333 liters. 4.94. If you don't believe me, do the math yourself, 1 liter is 61.0237 cubic inches.
u dont round up???
 

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I was just clarify it for the OP. The bores the same but the stroke is different. The taller deck height allows for a longer stroke than the 281 (4.6) can handle. The OP asked specifically about the 281 not the 330 (5.4). You can't get 351 ci out of a 4.6 block.
 
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