350 Engine Building Question

[David B.]

I am rebuilding my 1980 350, 4 bolt engine. I have done them before but came into conflicting advice on something and would appreciate input from the engine builders in this group. As all SBC's, the number 5 cap (rear main bearing cap)has an oil hole on one side next to the bolt hole. One rebuilding reference says to put a thin sealant coating around the oil passage hole when installing the #5 bearing cap to prevent oil leakage through the mating surfaces. Another reference (Graham Hansen's, "How to Build Big-Inch SBCs" (p.22) says to install a plug in this hole because without the plug, unfiltered oil can reach the bearing. It states that original blocks are shipped with this plug, which is frequently removed by machine shops for cleaning the block. Which is correct? Anybody know? Thanks Dave

[John H.]

Re: 350 Engine Building Question

That would be this plug, installed in all new blocks; Graham is correct - if you leave this plug out, oil will go directly to the main gallery and bypass the filter (the filter will fill up, but that oil will just sit there and not circulate, as pressure will be equal on the filter inlet and outlet). Make sure that plug is in place, or all manner of crud will get pumped through the bearings

[David B.]

350 Engine Building Question

Thanks John.