How to trouble shoot Ignition

I was running my boat awhile back at 3600 rpm's and it just shut down, like I turned the key to the off position. I now have no spark at the distributor end of the coil wire. I tested the coil with my Ohm meter and got 11,000 on the meter. What should I do next. The engine is a big block 350 hp with a Pertronix distributor. I am thinking maybe it has something to do with Oil Pressure Switch as now when I crank it over the oil pressure does not come up on the gauge like it used to. Whenit rose to around 20 to 25 psi on the gauge it would fire up. My engine seems to have a Sender and a Switch on the rear Port side lower part of engine. The Distributor is turning when I engage the startes. Thanks for any and all advice you can give.

Would help a bit knowing which vintage BBC you have....

Your next step with the ignition would be to check the primary side - need +12V on the + side of the coil and the - side needs to be grounded and then opened to make the sparks.

If you have a newer BBC with the electric fuel pump, you should have an oil pressure switch in that circuit...unless somebody has customized your wiring...

Makomark, I do not have an electric fuel pump. Thanks

with no electric pump, the only oil pressure switch should be for the warning horn circuit...now if somebody's hacked the wiring, that's a totally different can of worms. That said, focus on the ignition. if the primary side is intact, you can use a dwell meter to see if the ignitor is working. BTW, when you make a measurement, you need to tell us what you measured (and how) so we have a clue as to what you did.