Thunderdan
Well-Known Member
Up until '75, all U code (E86) 440's used nylon teeth on their timing chains, however beginning that year, the E86 engine was revised to an "endurance" engine, which featured many of the features outlined in Post #34, but also hard chromed exhaust valves, moly-filled compression rings to reduce wear, and of course, double roller timing chain, among other upgrades. This applied to 49 states, except Cali, which couldn't get the 'endurance' engine, which was primarily for law enforcement. The standard E-85 440 4 bbl (which also had a single exhaust and a measly 195hp in '78 tune) continued to use the nylon timing chain and standard parts through the end of the big block production in '78. The E86 Hi-Po also got the hotter camshaft through '78 which helped it achive the 255hp and 355 lb ft in it's final year, even with the lean-burn.
The E68 400's also got the "endurance" upgraded features in '75 as well as the E58 360 4 bbl.
That said, I also have a motorhome 440 from 1978 that has the double roller timing chain as well as the exhaust valve rotators, but the small E-85 cam, which all makes sense for a low-ish output application where durability is the objective.
