airbar 4 link on '69 bird trailing arm issues

[Tinker]

OK here's my first dumba## question. Currently fabbing the chassis for my firebird(yes I have been working on it, and pictures are coming shortly). Fitting the airbar w/ coilovers using stock 10 bolt/ multileaf BOP axle. Has anyone run into trailing arm length issues? The lowers seem to be about 1 inch short, and I need to keep the tire centered in the wheelwell, first looks, secondly I already had my aluminum driveshaft built last fall. i know it's a bit of cart before the horse, but I think you all know how projects and designs evolve before they are completed. Any thoughts on replacement? Do heims last very well on the street? I could fab up new control arms. suggestions please. Car never driven daily and if I get 1000 miles a year it would be a record. I am thinking of actually running this car at the track for enjoyment only.

[Vegas69]

Is your pinion anlge set correctly? That will affect the center line of your axle more than you think.

[Tinker]

Yes, it does change things. Today I finished fitting the rearend up and I can get it to fit, but I have 6 degrees upward pinion angle. To make matters worse, my rearend is higher than my tailshaft, increasing u-joint angle to around nine degrees. I don't think it will last too long. Now I must look at changing the engine angle, and still lose 3-4 degrees pinion.

[Vegas69]

Been there done that man. If you can get 4 degrees negative driveline angle and 3.5 positive pinion you should be close to center. Mine is almost perfect but it's a 69 Camaro. If you are low like me then it may be best to cut the tunnel now. I don't have driveline vibrations but if I had it all to do over again I would cut the tunnell and run 2-3 degrees of driveline angle.

[Tinker]

Thanks for the info, i'll try to persuade the motor/tranny up a bit, and most likely lengthen the trailing arms. Thought I was done welding the floor, maybe not. It's all apart now, so I'd be dumb not to do it the right way now.