Newbie with another disc brake swap question. . . . .

[dennis111]

I have enjoy checking out the forum an the different reader's rides. Since this is my first post, I decided to make it a good, challenging one.

After reading several articles and the FAQ about converting my 68' GMC PU (see sig.) to disc brakes I purchased a complete 1978 Chevy 1/2 ton V8 PU with PB and PS. I also has a 12 bolt rear which is similar to mine, except it has the desired 5 lugs.

I understand that it is easiest to change out the whole crossmember assembly in the front. I also understand that the engine will need to be lifted up or removed and to use the 78's proportional valve. This leads to some specific questions that the various articles didn't cover.

1. Apparently the 78' crossmember will fit fine, if new holes are drilled in the frame. How does one know where to drill the holes in the frame? Are there holes or anything that will help for forward/rear alignment?

2. Which motor mount metal bracket works best? If I decide to reuse the original 68' brackets, do the holes in the 78' crossmember match?

3. Do I use the 78's pitman and idler arms? I have the late 68' type steering similar to the newer trucks.

Any other words of advice?

Now as far as the rear end. What will I need to do to put it in my 68'? I am led to believe that the leaf springs pads might be the same distance apart. I have noticed that the shocks in the 78' are in different directions and they are located outboard of the frame.

1. Should I try to mount the shocks outboard or should I reweld the old mounts/bumper pads on the new rear and use the original 68' locations? I am looking for the "easiest" way.

2. Is there anything else that I have missed that would put a monkey wrench in the swap?

Now for my last question:

The leaf springs appear to be the same width. Are they swapable without major modifications?

Thank you for your input and suggestions. Hopefully your answers will help future newbies too. . . . . .

Dennis