Yet another slip yoke question? Optimal depth?

I must have mismeasured a tad because my slip yoke is about 1.5" out of the tailshaft, instead of the recomended 3/4" to 1".

I probably am being OCD about this, but I like to get things right.

My understanding is that the splined region of the output shaft is 3.45" My slip yoke seems to have about 5.00" of tube showing on the outside.

I have about 1/2" shaft showing beyond the seal. I can get the yoke to pretty much go all the way in to the seal, which tells me the splines continue into the U-joint casting about 1/2" If that were not the case, then the slip joint would not go all the way in to the tail housing right? So the shaft can go 5.5 inches into my slip yoke.

So my math says that when I have my yoke all the way in, there is 3.5" of splines engaged (the forward 2" of the slip yoke sits "free" over an unsplined area of the output shaft), and even when the yoke is pulled out 1.5", the splines are still fully engaged (5.5 minus 1.5 is still 4" of yoke on the splines)

When I lift the rear of the pickup by the frame, to allow the suspension to maximally fall down, the slip yoke comes out another 1/4" inch. Splines should still be engaged, right?

So I have convinced myself that, while not optimal, my yoke is still adaquately deep in the tranny.

Now, there are more torsional forces on the longer setup, but I am running a very mild 240 I6 and it no longer does any real work. I think I am OK.

You agree?

I would agree with you. The input shaft on a C4 (non-hardened) only has about 5/8" in the splines and is less than an inch in diameter. Your driveline yoke is supported by a bushing and engages a lot more of the shaft than the input on the tranny. I don't see any way that you could be in trouble.