Originally Posted by Paul Kane
429s and 460s use a massive and strong 9/16-diameter head bolt that handles a torque/clamping force of a whopping 135 lbs-ft. (Compare to chebby's 7/16 bolt which is torques to 65/75 foot pounds.) The original 429/460 head bolts are very strong and of high quality, and if well preserved can be reused over and over again in most applications, certainly most naturally aspirated applications.
Many moons ago (before there were 460 parts everywhere), the car pictured below ran 7.20's in the quarter using an unmodified oem useed 2-bolt block (4.44" bore), oem used 460 cast crankshaft, oem used iron passenger car heads, oem used main bolts and oem used head bolts. The Moroso calculator put HP at over 1800HP.
(Kids, don't try this at home; your results may vary ;) )
Paul