Frank, Quick correction .... the 390/401 has larger ROD BEARINGS ... main bearings are the same diameter as the 290-360 motors. Sincerely, Greg Taylor :) <>< --- On Tue, 11/11/08, Frank Swygert <farna@xxxxxxx> wrote: From: Frank Swygert <farna@xxxxxxx> Subject: Re: [Amc-list] 390 vs. 401 crank casting numbers .... To: amc-list@xxxxxxxxxxxx Date: Tuesday, November 11, 2008, 4:48 PM 390/401 has larger main bearings, but the forged crank mains can be turned down to fit 304/360 blocks. Might be able to line bore the block for the bigger journals too. The bottom of the 304/360 cylinders have to be notched a little to clear the longer throw of the 390/401 crank. Once the crank is fitted and rods mounted rotate the assembly and note where the clearance needs to be ground. That can be done with a die grinder since it's not rotating mass (doesn't affect balance). There needs to be at minimum of 0.020" clearance between the rod bolts and the block, a little more wouldn't hurt a thing! -------------- next part -------------- An HTML attachment was scrubbed... URL: http://splatter.wps.com/pipermail/amc-list/attachments/20081111/b995af75/attachment.htm _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list