tripod joints

what effect will be seen if the tripod joints used on the gearbox side of the driveshaft are replaced with rzeppa joint?

Plunging shouldn't cause any axial load, if that is what you're asking. Unless of course you are exceeding the amount of permissible plunge...

Find how much plunge is required by your suspension for the range you want to run and compare that with how much plunge you can get out of your axle. If you need more plunge than you can get, you're in some trouble...

Otto.
I was thinking of using CV(Rzheppa joints) at both ends while considering the suspension geometry and reducing the net plunge throughout the travel and accomodating it in axle plunge since there is no tripod.
Is that not advisable.

we ran a suspension that by its geometry has a lot of plunge i oder to get the other characteristics we wanted. what we found is one of the Bombardier Can-Am products runs a rzheppa style CV pair where both the inner AND outter are capable of plunge. the entire setup can accomidate for up to 3 inches if my memory serves me correctly, as well as can handle some good angles at each end. The downside was that thiese joints were fairly heavy compaired to other rzheppa joints on the market. another option we considered for a future modification (note we ended up changing the geometry instead) was to use a regular rzheppa joint pair that could handle the angles we needed and then install a telescoping shaft to handle the plunge. 

play around with your suspension geometry and the location of your inboard CV's try and reduce the angles of the shafts to as little as possible. this will help eleminate some plunge. an easy way of doing this is by moving the inners as close to the center of the car as you can.