Technical SBC replacement main bearing caps

Yup. If you can find a set of caps that fit the engine then buy a lottery ticket 'cause you got lucky. Variances in machining happen and no two blocks are identical in the bore locations, bolt locations and the like. Even things like the Ford 9 inch carrier caps are unique and can't be interchanged.

Machining variances are a fact of life. I've read where guys went through a bunch of caps to find ones that are close and they still require a line bore to get things straight.

 

If there is any offset in the fit of the cap it turns the bearing ends into oil s****ers. If you are lucky the crank will lock up on the bench, if not, you get an expensive lesson when it fails under load.

 

First step is to go check with the machine shop you use or the local go to machine shop and see it they will even line bore it if you pick up used caps for it and see what the costs and who knows, they might even have a bad block out back with a set of caps on it. Still as several others said 4 bolt 350's aren't that expesive anymore as more and more people with later model stuff are going to LS instead.

 

Personally for an engine build I prefer to start with a two bolt block. And don't need the original main caps. First thing on order list is splayed main caps. Splayed four bolt main converted two bolt equals stronger than factory four bolt. Unfortunately I keep ending up with factory four bolt engines lol. At least the later model 350 I have for my 54 is a 2 bolt. So it may actually get built at some point