"Shovelheads always needed a top end job done by 25-30K miles, no matter what you did to them." Fact. And the English bikes (the older Triumph, BSA's and Norton's) seem to need top ends more often than that. No matter what I preach to owners about warming up the engine before giving it the onion . I do not see to many Shovel's, or any other bike I repair or rebuild, with that many miles on them. But what I do see is abuse and neglect. But the Shovel and Ironhead Sportster's do require torque plates for boring as per Harley Davidson manual and suggested for the Pan, Knuckle and various Side Valves.