Dom, I am sure DOHC is more expensive, but then how does Ford make it work from the cost aspect? Or do they just get the accountants to go along with "this is a better idea even though it's more money to produce." Okay, I have a lot of sour grapes toward the BOD at GM! They forced my hero to retire, JMHO, for the sin of thinking waaaay outside the box!
Back in the old days a sb chevy had a plastic liner on the cam gear for teeth. They broke at the first really cold temps after 40k miles usually. The truck motors used to get a steel gear, and they just would wear out eventually I guess. I've never seen one fail, but I'm sure there was a point at which it would wear out. My Cobalt uses a 2.4 DOHC/4V 4 cyl with chains...or at least I think that's what I saw in the FSM. I do less maintenance to that motor than I do to my LT5! I have 35k on the OE plugs and have yet to see a drop in gas mileage. The Tech told me 50k on the plugs or if a coil fails, which ever comes first.
Dave, not to be a smart a$$....but vettes always used truck parts, motors especially. Among the blocks available to choose from, the Heavy Duty truck block 350 with the casting I. D. # ending in "010" was the one you looked for. As a cost cutting measure from 73 onward they used the medium duty truck block. The 010 block told you that at least if the vette you were looking at had the right block anyway, or if it was a cheap & quick fix for a blown motor. The 010 blocks were 25 and 50 lbs heavier ( respectively ) than a Med duty or light duty block and it was in the cam and main webs mostly to counter stress that payload would cause. That's one of the reasons truck blocks were prized by the junk yard shoppers looking to build a stout sb. for spirited use.
You'd be surprised to learn how many "borrowed" part there were in a C2 & C3 while they were at the St. Louis plant! LOL
Tom