Ok i am currently putting togther a 408 stroker ,Eagle H beams (needed very little clearancing )small notch in each opposing bore to clear rod bolt . (my Eagle rods are great all within .0007 of each other center to center length was all about 6.125).For any thing but an all out race motor i wouldnt wast my money on internal ballance (quoted $750 in Oz to get malory in mine )a quatity ballancer (360 type )and a B&M weighted flex plate then get this assembley balanced works for me( it will only see 6200 rpm ) .I agree with a cam choice of around 240 to 250 @50 (i will run an Engle hyd)10:1 comp single plane manifold and some ported heads . Will be a dream on the steet and strip . My 360 thati am still running is like above and runs 12s @ 109.1 mph in 68 Valiant.