this head should work great for 400. one of my trucks has a forklift head on it, found it out when i went to swap the rocker arms out for manually adjusted ones. the forklift head uses cam bearings, the trucks do not. it runs better than my other two trucks and makes more power and oddly 3 more mpgs. if you ever find a forklift that someone is parting out, check to see if it has a 4g64. my dad used to own one but this was before i was a mm guy. they can be found in clarks and cats. they are propane to so might be a project. good luck.

http://www.ebay.com/itm/4G64-8-VALVE...29dd51&vxp=mtr