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By Happychipy
#97771
Hi I’m looking for information , I have a 1942 350cc OHV WD/CO outfit. I would like to fit a 500cc OHV engine (J2) or can I put the Barrel and head from a J2 on a 350cc Engine casing ? Thanks
By vince
#97774
Hi, a quick look at the parts books shows different base gaskets and bearing in mind that there is a 14mm difference in bore size I doubt if the top end with interchange. However I am lead to believe the complete engine will fit. Vince
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By Adrian
#97782
Probably a lot easier to do that.

For the later Bullet engines it is possible to modify a set of 350 crankcases to take the 500 top end. The crankcase mouth has to be bored out, and the cylinder stud holes welded or plugged up , then re-drilled and tapped for the 500 cylinder's studs on a wider spacing. Not rocket science, but I don't know if this could be done with the WDCO or Model G crankcases.

A.
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By Allanfox
#97788
I would think a more recent 500 iron barrel engine would fit, probably easier to find and they don't look that different?
By Marko
#97963
I dont think it can be done; a friend of mine in France looked into it & decided to give it a miss. Although the 350 & 500 (G, CO, j2) share lots of components & look very similar i'm pretty sure the frames are different too. The crankcase mouth would have to be machined out & a host of other things too

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