I am making the brackets for an LS1 disk conversion to 68 firebird drum spindles. There seems to be about .040" difference between the two as i am trying to machine the bracket. I am pretty sure the left and right spindles are interchangable, but can someone verify this? Assuming they are the same it looks like i am facing a bent spindle.

I found the faces of the spindle bosses to not be parallel. Depending on how you're measuring them, this could throw you off.

I have two partially machined brackets if you're interested. The holes and overall shape are done, you just need to cut some reliefs to get the offset right. I did this swap on my car and love it.

Take and bolt a straight bar onto the steering arm and rotate it up to the top bolt boss and that will be what you need to make them the same.

I went through ALL this creating my "pdqCBB" front set-up big, single piston caliper bracket template!

I'd shim it the needed amount and go.

pdq67

http://home.att.net/~bhandlon/pictures/67/img073.jpg
http://home.att.net/~bhandlon/pictures/67/img074.jpg
http://home.att.net/~bhandlon/pictures/67/img075.jpg


My camera is broke so the pics are from my phone, but let me describe what i have a little better. Spindles are off the car. Caliper plates from 1/4" steel plate are drilled, cut out & bolted to the spindles. Hubs are turned down & bolted back on the spindle. Rotor is bolted on the hub (still need to install new studs, going with 12mm). Caliper bracket is bolted to adaptor plates. I am attempting to center the rotor inside the caliper bracket. As you can see from img073 the spindle has not been machined down. I have decided to machine the adaptor bracket down instead (it will need about 0.050” machined off to center the rotor inside the caliper bracket). Both left and right are within 5 thousands of each other so the top of the spindle is really good. I know most people machine the spindle, but my thougths are since the adaptor plate is already custom I would leave the spindle stock. My issue is the gaps on the bottom side don’t match between the two spindles (left vs. right). Looks like I will have to shim the bottom out about 0.40” on one side and the other will be very close to being right on (meaning left vs. right spindle). I was wondering if this difference is normal or is my spindle bent? Again i am also assuming left and right spindles are the same part number.

I had a .144" difference between the two bosses, IIRC. We put the spindle in a lathe to measure the difference. I originally tried the method PDQ suggests and got some erroneous readings because the faces of the spindle bosses were not parrallel to each other or perpendicular to the spindle shaft. Once I got the correct offset for the spindle, the bracket centered up well. I did mine the same way you are doing.