HEy i am new here and this has probably been covered before. I searched with no luck but anyways, how can I tell if the engine has a four bolt main from the outside while still in a car (in a jukeyard)?

 

you would need to look up the casting number.i dont think there is a appearance difference in a 2-bolt or 4-bolt block.if you have the numbers go to www.mortec.com and look it up

 

There is no external difference between 4 bolt and 2 bolt main set up. Even the casting numbers are the same, the difference takes place during the machining operation at the factory. However; there are some special purpose blocks that are not installed on the assembly line, such as the Bow Tie blocks, that only come with 4 bolt mains.

 

you can usually get a good guess by the year and what it came out of. not a true read but you are bettering your chances