Johnny, hello. Trust you've had a Merry Christmas. Curious, where do you "hail" from? Am, about forty miles N of KC, MO.
Couple of ?'s. How did you determine you had a hole in a sleeve? How extensive is an in frame overhaul? And, where did you find parts if you didn't find what you need on YT?
You've got a good point re: sending unit. Thinking I'll try a mechanical gauge to confirm oil psi.
Consider this theory to see if my logic "holds water", thinking the fuel psi issue may be a result of a faulty fuel relief valve. Late model '66's have an integral relief valve between the first and second stage filters. The transfer pump pulls fuel from the first stage and returns to the second stage. The relief opens to the first stage when the second stage is over pressurized. Thinking the relief is not functioning creating over pressure in the entire fuel loop.
Thinking the low idle rpm is as simple as adjusting the linkage. If so, it may be the simplest problem I'll face on this project.
Look forward to your reply. Thanks.