You would first have to decide what was the final CID you wished to get from this combo. A quick seach on the net yeilded quite a few different combinations.Heres just one posting I found for a 408cid motor:
: You'll need to get a grinder to cut some of the material off of the counterweights. I personally made me a pattern from a piece of cardboard taken from a 351W crank and outlined it on the 400M crank and marked it with a red pencil. Grind the counterweights to match the pattern. After you do the grinding, take the crank to the machine shop to cut the step off of the front of the crank so that the timing gears will line up. Depending on what year 351W block you have, you will need the machine to either cut down or cut off the oil slinger at the rear of the crank. A new keyway needs to be cut at the front of the crank after the step is cut back. As for as rods go you can either use 300 6cyl truck rods that will need the big end narrowed and the rod journals on the crank machined from 2.311" to 2.125", or you could just buy some aftermarket H-beam rods that are 6.2" long designed for a stock 351W. This will save you on machine cost and you have a stronger rod with the Chevy pin diameter. You can get pistons from many different manufactures. Keith Black has one with a 1.28" comp height
Do a search for" 400m crank in a 351w" for more
Greg B
