They took weight reduction to a crazy level in these 2 engines, they removed 2 rows of links on the timing chains and narrowed the timing gears in their quest to cut weight.
The conventional timing chain and gears can be substituted without any changes, but think of retooling for thinner timing chains and gears to save a few ounces..............crazy
The early blocks (77-79) also had all the nickel removed from the blocks. They were incredibly soft and wore the bores out really quickly. At 60,000 miles you had to cut the ridge out of the blocks just to remove a piston. I've routinely disassembled older Stratostreak engines and even at 150,000 miles you could still remove the pistons without cutting the ridge out of the cylinders. This was the time that all the GM lines cut costs by removing alloys that improved the cast iron for wear resistance. I guess accountants thought no one would realize the engines were wearing out sooner and save 50 cents per car........
This was really when GM lost their market share, and never would regain it...............
