Thanks for the great info, Mark! 
Are there "early" and "late" versions of the '76; or is it just a matter of digging in and seeing what I've got? (The latter, no doubt. 
)
I can't WAIT to receive the book and dig into THAT. 
There are 3 actually distinct versions of the 750K6 that I have seen: the early, the middle and the last version.
-The early ones used mostly leftover K5 and some F0 parts, mixed in the engines and wiring harnesses. These engines had "K" bottom ends with the dual-sprung clutch steel plates and the "F" clutch basket to make them fit, so the top clutch plate is different from the others. These engines sometimes had F0 heads (392 casting mark in the back) on top of K5 cylinders and pistons. The carb bodies were the same ones used in the F0 bikes, but with the K5 jetting and needles (K27102 needle numbers). These engines only developed around 48 HP because the compression was only about 8.8:1.
-The middle ones had the "K" heads back on them, with "K" pistons and cylinders and "087a" marked carbs. These carbs are much like the regular K5 carbs except for the air screws, which originally had little plastic caps on them that prevented them being turned more than 1/2 turn in any direction off of normal (this was a Carter era EPA "fix" that was supposed to keep us from 'illegally modifying idle air mixtures and thus emitting excessive hydrocarbons' and was found in cars, too). We just removed and pitched the caps after they cracked, at about 10k miles. You can use a regular air screw in its place, they are internally the same as the K5 carbs. Some of these carbs are marked just "7A". The wiring harnesses were like the early ones, with little jumper wires using bands of color on a colored wire to indicate which end was being jumered into another circuit, as the main wiring harness body was K5 but the handlebar wiring was F0. These engines made about 52-55 HP.
-The late K6 is the best-performing 'K' bike (stock) since the early K1 bikes. It has the K5 bottom end with the F0 top end, Stellite valve guides and all! It has the F0 cam with the above-mentioned carbs, but with the jet needles from the F0 bikes (K132107 or K132102 or K13nnn needles). The important part to note here is the upper end of these needles in the F0/1 bikes have a thicker section that extends further down the needle before the taper begins. This matches to the late-intake-valve-opening of the F0 cam and prevent plug fouling problems: if the earlier carbs are used with these cams, plug fouling is constant and unfixable without these special needles. Using Keyster's needles will also reduce plug fouling in these unique engines, but will also reduce HP considerably. This combination was/is the hotrod version. I haven't seen HP figures for one, but I know from riding them that they will easily exceed the ton in 4th gear and feel much like the K0 in the lower gears. My butt-dyno would estimate them at around 70-72 HP.
