hello Furious
The changeover year was 1970. The changes were mostly bolt-on stuff.The long blocks were the same except for tuning(Things like cams, and pistons). Ok so the blocks were the same.Except for cid. And except for the drivers side motor-mount; which has 2 styles and matching brackets.And except there were several different heads.Ok let me rephrase that; any year long block can be installed in any year chassis with a minimum amount of fuss. Ok, thats got it,now.
-You already know about the front end. The older stuff (67 to 69) was sorta geared around the radiator. It had a drivers side lower spout, so the cast-iron waterpump picked up on that side.Well that meant that the timing tab and dampener had to be on the passenger side. It was also pretty crowded with the power steering pump there, on the drivers side.
-So in 1970, they flip-flopped everything. The rad spout went to the pass. side along with a new aluminum water pump. Of course the timing tab had to go, which was a part of the cover, so a new cover came out, as well as a newly marked dampener. The P/S pump now had lots of room.
The package specific parts are; rad,pump,T-cover,and,all brackets. The dampener and crank pulley are also package specific, but they can be massaged to work either way.The dampener can be reindexed as to timing marks, or a timing tape installed, and if you make your own timing tab you can use either T-cover.
-If you treat the systems as a package, you can swap the package around onto any LA in most any year chassis. The stumbling blocks are; if you are stuck using certain parts.
-I have the later style front end on my 68 FormulaS clone. I just liked the looks of the later parts better, and I happened to have a 1973 A/C 26" rad kicking around, and the pump I wanted to use only came in the late style.
-There were other changes as well, but they mostly get swapped out on a performance build. Things like;intake and carb(71),cams,engine brackets(73),dizzys,air filter housings,ignition systems,etc.
-Exhaust manifolds are sorta chassis specific, but also year specific as well.
-One more thing; There were several small block cranks offered over the years. Some cast,some forged.Some internally balanced and some externally. So, the dampeners are not universally interchangeable, even though any one fits on any crank. When you go engine shopping, be sure the correct dampener is on there.
Hope that helps.
