Thread: attempting to rebuild my 390.

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stock 390's have a bore of4.05 and a stroke of 3.78. the easy way to increase cid is to get some 410 pistons rods and crank and with no machine work you have 20 more cube's.410's were found in mercury's. with the longer stroke gives more low end torque. what year is the 390? i've built up several 428's in the past and they all had 352 cast into the front of the block.


also have the block sonic tested most 390's won't take the overbore to make a 406. a .030 or .060 overbore on the 410 pistns would be ok but i'd go with n.030. 410 is 4.05x3.98. it's basicly a 428 crank in a 390 block with different pistons. and as far a smoking hondas i think your barking up the wrong tree. i've owned several honda h/bs and with a little work can be real killers.also what transmission do you have? c-6,3-speed manual,4-speed manual.if you have the c-6 your going to need a shift kit in it.after a good rebuild.