Brake booster push rod issue

[MYOUNG]

I am attempting to convert my 69 GMC C2500 with Drum/Drum brakes to a Disk/Drum setup from an 84 GMC 2500.

I have replaced the entire system with all new components including the combination valve and master cylinder.

I have everything completed except the push rod in my original 69 booster is too long. I have tried looking for a replacement but none of them look correct. I need a short push rod that fits in my booster.

I considered cutting it down by 1 5/16" to correct the issue but I figured there might be an better way to correct this.

Do I have to switch out the booster now also??

Is there a dual diaphragm type that will bolt up without adapters etc??