Time for a Long block?

"The car starts fine, cold or hot, but lacks power and stalls if I give it too much gas from a stop. Now I can turn a wrench pretty good but I couldn’t diagnose my way out of a paper bag, so I finally broke down and took it to a mechanic someone recommended. Well the diagnosis is in; no compression on cylinders 1, 2 and 3; valve leakage and crank case leakage."

Does anybody spot a contradiction here?
I don't understand how your slanty, with 3 cylinders at zero compression, starts fine, cold or hot............
Lacks power ; I get that!
Ima thinkin it's time for a valve adjustment, a quick check of the seat pressure, and a leakdown test. Make sure to knock the carbon off the valve sealing face,before the adjustment. I do this with the piston going down on the power stroke.
The quick check is to attempt to spin the intake spring, with the valve on the seat.If one or more is considerably looser than the others, or worse flops around,then it's time for a valvejob. With high mileage pre 70/71 engines,comes valve seat recession, as well as seat wear, and a loss of seat pressure is a sure tell.