TH 400 Slip Yoke Travel

[71 Nova]

Question guys. I swapped out the TH350 in my Nova for a TH400 and swapped the driveshaft yoke for a 400 type yoke. The slip yoke travel from u-joint fully seated on the rear end yoke to slip yoke fully seated in the back of the trans is just under 1/2", which is too tight. Nova is a leaf spring rear setup with CE Slide-a-Link bars. What should the nominal travel be? For reference, Denny's driveshaft recommeds 3/4" to 1".
Recommedations?

[supernova]

3/4" - 1" sounds right.