I know this may be a long shot.. Here's my question.. Are all chevy truck engines 4bolt mains? I might be buying a 1977 Suburban 3/4 ton with a 350 in it.. I'm not sure if it's original.. I'm going to find out this weekend I hope.. I'm just hoping it's a 4 bolt main engine... Thanks guys.. It's better to have it and not need it, than to need it and not have it.