Valve cover clearance.

[psoucy]

Have done a complete frame off restoration on my 70 k10 w/ 350 TH 350 and I’m having clearance issues with tall valve covers and and an MSD ignition/ distributor. Valve cover hits engine well along with the distributor. Does the engine crossmember and perch have an offset in it and needs to be installed with the offset towards the front. It appears the center of the 2 mounting bolts of the perch/crossmember are offset of the center of the engine mounts that would account for the engine being too close to the firewall. Anyone have pictures of an unmolested 70 frame so I can compare with what I have now. Thanks in advance.