I know this is an old thread but I thought this would be a good place to put it...
I rebuilt the engine in my deuce and I still have blowby issues. I hate that it didn't turn out good and It does not make me happy at all. I am toying around with the idea of putting a 4-71 Detroit in my truck if this engine ever pops its cookies. According to the specs, its close to the same weight as the multifuel, N/A version is 160 horsepower and 407 ft/lbs of torque... which is pretty much between LDT and LDS power... but closer to LDS. Rear mounts should be the same as they are SAE and the front mount might need to be fabricated. I would also spring for putting jake brakes on the heads as well. Right now I am just kicking around the idea. I might take one more chance at putting new rings in it, honing the cylinders, new rings and putting it on the dyno to make it grunt for a long time. If I still cant get the engine to not have any blowby, then I'll dump a 4-71 in it and call it a day.