A quick update. I pulled the mechanical fuel pump yesterday and the push rod. I was shocked to find the rod was 2 3/4 inches and not the 3 1/4 inch. Everywhere I check indicates the push rod should be 3 1/4 inch. I've ordered up a new pushrod and will see if I can run on mechanical pump alone. You just can't assume the correct parts. I bought this engine complete and then had it rebuilt and somewhere along the line the pushrod was changed out. The car same with an electric pusher pump already installed so when I had trouble the easiest and quickest solution was to use the electric pump. I' gonna feel a little foolish if this works!