Low oil pressure on SBC
 

A long time ago I had a problem with my 307 sbc with low oil pressure. I rebuilt the 307 with new crank bearings, and replace with a high pressure oil pump. Once I had the 307 together and had it running, the oil pressure was very low at 40psi cold, and 5-10psi hot. It should read 80 psi cold, and 40psi hot. I discovered the distributor was cause of the problem. The oil travel around the groove of the distributor housing then through the lifter gallery was leaking. I replaced the distributor with another one and to my supprise the oil pressure jumped up 80psi cold and 40psi hot. If any of you guys have low oil pressure on your sbc, before you take the block apart, check the distributor.

That's a good tip! If the dist. housing was wobbling around a little, over time it could loose it's size and leak a lot of oil right back into the pan.

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what do you mean by the housing was leaking?? i have a 350 and has very low oil pressure. change the oil from 10.30 to 20.50 and pressure comes up everywhere. just wanted to check about the distrib housing. problem thanks

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also on that note how old was your distributor that was the problem one

The distributor body forms part of the oil passage- that's the "groove" seen down near the gear in the photo below. If the dist. body was machined undersized or was damaged/excessively worn, this would create an internal oil leak from the groove that would dump oil back into the pan- and might also lower the oil pressure.

http://chevythunder.com/lg_HEI_2.jpg