My 76 F250 4x4's 390 has spun a bearing. Should I pull the heads and pull the piston's to see if the rod (bearing end) is out-of-round, or is it safe to just replace the crank and bearings? I'm looking at $65.00 for a complete gasket set versus $20.00 for the pan & timing set gaskets.
The heads were reworked about 25,000 miles ago (previous owner).

 

Along with rcank and bearing replecement, I'd go ahead and have the rod checked, just to be sure.

 

If your bearing spun, rod or main? Your rod will be bad, replace the rod, recondition rods are not very expensive.If your main spun, Major problems, normally cheaper to replace the block.

Are you having the crank cut?

Advise

Dave

 

Usually a spun rod bearing wipes out the crank and rod. Final branch on your decision tree may say "short block rebuild". If you are already going to pull the crank and heads we're only talking about a new set of rings (assuming bore is in spec). HTH
FL Panhandle