426 big bore

1 reply to this topic
  • dktraw

Posted February 17, 2012 - 07:39 AM


hey guys, buddy of mine is looking at getting a 4stroke thumper, and hes found a couple to look at. but my question is, one of them is a 426 with a supposed 486 big bore, but i cant find any 486 big bores available for the 426. is it something that they used to make, but discontinued? is it a reliable kit? any info would be great, thanks

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  • grayracer513

Posted February 17, 2012 - 09:25 AM


A 2mm overbore in a 426 comes out 444cc. 2mm is about as big as is practical, and a 3mm, if anyone ever made one, would be 453cc. 486 would require a 101mm bore, whereas the stock cylinder is 95. Even if someone had used a 2mm overbore and used a stroker kit to reach 486, they'd have to add a whopping 6mm to the stroke.

The Marine Corps brass refers to this sort of thing as Bovine Scatology, but the Marines in the field just call it "BS".

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