parallel 4 link

I have 88 cab plus mazda ...Can any one please tell me what length my tubing should be on top and bottom

As long as possible. Were you going to use the factory leaf perches for the lower bars? Measure it. Measure it. Measure it.

Thanks....... so does 25" sound good ....yea using stock frme mount.

Factory leaf perches will hold you up from laying frame. I'd put new tabs on a new crossmember.