V-8 crossmember
 

I'm replacing my inline 6 and transmission with a chevy 350 and automatic transmission in my 67 GMC Handi-Bus. I need to replace the engine perches with v-8 perches. I'm ok with replacing the entire cross member. GM put v-8s in those starting in 68. Where can I find new or used perches or cross member? I prefer OEM parts.