rustynail:
The clearance of the valve covers, distributor and air cleaner is rather minimal with a V8 application. Converting to an HEI also makes the distributor rather close, but it will clear. Perhaps a set of short small block V8 valve covers in place of your tall ones will eliminate your clearance issues at the firewall. This will avoid shifting the motor mount location forward, which can be done, but is rather involved. Good luck with your '65 C10 project.
