Hi John,

I looked into fitting a stroker marine crank into a B20, but like stated earlier, it wont fit, although with some mods, it just might.

You would be looking at a AQ151 or a AQ171 block for the forged marine crank, with 86mm stroke. The Pentas use a small ID plate on the starter section of the block. The AQ151 was produced in small main (55mm) format and changed over to the 63mm main: blocks produced before 1988 used small mains and little rods, 1988 and up use 63mm mains and big rods. I think the 171's all have large mains. I believe the stroker cranks use the stock conrods but use a shorter piston (compression height) to compensate for the longer stroke.

These stroker cranks are not very common unfortunately, and often pricey... so I'm not sure wether wheter you could modify those cranks to fit a B20 at low costs. (granted you would find a bunch of them in the first place).

Hope this helps.

Where does your own 2.5 ltr B20 stroker crank originate from? Welded and grinded B20, or is it a complete new cast?

cheers, ben

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P131, '65, B20B+M47. P131, '69, B20E+AW71L+LSD. (www.tinustechniek.tk)