My 55-57 235 engine sometimes looses all oil pressure. I have the type of oil pump with the floating arm; is this the correct pump and if not which one should I use? What would cause the pump to looses pressure on a hot day? The pump looks ok and performs normally most of the time. Is the float set too high?

ron

The floating screen was used i 1955 only . Many caused problems (lost prime) when new and 1956 style pumps were installed under warranty.
If it were my car I would consider replacinng the pump and screen.....eaiser than replacing the crankshaft.

Interesting, this is exactly what happened on my engine. I'll replace the pump and have to modify the oil pan baffle as the original oil pan will not allow a different type of pump to fit. Hope I didn't ruin the bearings. Thanks for this info.