'68 318 to carbed Magnum 5.2: Check my checklist
It's not unlikely they added the roller cam blocks and roller cams into the vehicles they did to test the water much like they did with the Imperial's TBI. While the cars certainly weren't premium cars, Chrysler didn't offer anything larger or more akin to a luxury car at that time.
Only thing is, what's the good of testing a roller cam block without the roller cam? Nobody would know except anyone who pulled the manifold.
I could see production of roller blocks a year before rollout, but three years before sounds a bit unusual. Oh well, sure makes it easier for '85-87 owners to go roller cam with the factory spider, if they wish.
There's little value of all 318s outside of and even within those enthusiast circles, and the majority who care that they have a motor that does anything but run follow along the lines of the older MoPar enthusiasts- they don't care all that much if it is flat tappet or not since the cams are inexpensive. I've seen many a TBI truck with an older motor. That's of note since it's not exactly like any 318s are above or below another. Some folks build strong 318 roller cam motors or strong 318 Magnum motors and part of the reason's due to the 318's value typically meaning a good motor cheap.
...and if someone does care about a roller cam, they default straight to the Magnum to get the benefit of the improved heads, thus leaving the TBI engines to gather dust in a small part of the history books.
I'm not sure how much of it necessarily even has to do with the motors. From what I've heard secondhand- it sounds like the valve seals weren't as good on the smog motors, and part of that is like the modern motors the smog engines have greater recollections among many for having over 300k miles while most of the older cars are a total unknown. Most of the ones that weren't run hard and put up wet had around 200hp. Many of the higher HP 360s really have tons in common with the smog motors- just they're not identical- the E58s and Magnums being in that category.
Maybe so, but it still doesn't explain the lack of attention or interest - especially when most builds seem to involve replacing pistons, an aftermarket camshaft, and a desire to seek the best heads possible.
With exception to the heads, that means almost everything associated with a smog block goes in the trash to begin with (except heads, which may be the only reason to seek out one engine vs. another for a budget performance build) thus, what's the concern about the smog heritage to begin with? You're left with a block which is - essentially - no different than the non-smoggers.
Heck, prior to the Magnums, the 308 heads off this 360 were amongst the best to port - and need I mention that it has air injection ports? SMOG HEADS! RUN AWAY! #-o
Of course, this doesn't apply to cases wherein a manufacturer may modify the block rather than pistons and cam - such Ford's own bastardization of the 351C into the 400/351M - and even in that particular case, the rightfully-hated 400 (and that's coming from a fellow who lives on both sides of the Ford/Mopar fence) can be made into a respectable street motor with a proper set of flat-top pistons and a cam.
By comparison, the Mopar builds have it a lot easier - you don't even have to worry about intake choices due to a taller deck height (and therefore wider intake valley).
But, then again, I'm not trying to build a performance monster - so what do I know? I'm just trying to build a nice, streetable LA out of a junkyard motor, with the best "simple parts" I can swap.
Think they'll clear the PS and the firewall?
Well, that is my dirty little secret - the whole swap is going into the B-body shown in my avatar; not the Valiant behind it (nobody touches my slant six!). I just get better advice at FABO ;)
I have more to worry about clearing the 904's shift linkage on the driver's side than anything else. Close clearances at the power steering pump are possible, but it looks as if it should clear with no more issue than the same manifolds in an M-body (which have been documented @ Dippy.org).
-Kurt