BACK IN THE ’60S, Chrysler engines were overbuilt—generally, stronger than they needed to be. Still, factory hi-po versions generally left the factory with many small, but significant upgrades—better rings, con rods, crankshafts with special surface treatments, tri-metal bearings, high pressure oil pump, roller timing chains, et. al. Some, such as the 340 6-Pack of 1970, had beefed main bearing webs which gave you the meat to install 4 fasteners per bearing cap if you were so inclined. The ultimate was, of course, the 426 Hemi—with cross-bolted (screwed, really) main bearing caps.
The more things change, the more they stay the same. The early 5.7L Hemis were strong enough—just. Later 5.7Ls, the 6.1, then 6.4L versions were each significantly beefier than their predecessors. For the Hellcat, then the Demon and Redeye,…