On another site we are having a discussion on what locates the main bearing caps on 55 and up 235-261 engines.The rear main has dowels. The other three have nothing,no dowels,no register cut into the block.
Some say the shoulder on the bolts locate the cap.some say the assembler has to hand fit the cap by tapping it with a hammer.And some say it's just is magic.
Does anyone have a factory manual for 55 and up engines describing this assembly procedure.
Or opinions from actual experience?

My factory 1955(0nly) Chevy manual really doesn't describe the fitment of the bearings other than to say: Draw bolts up until caps are snug to the crankshaft bearing journals. Also .002 shims are the starting point on the caps.

In the past I just felt the cap(s) edges for alignment as I tightened toward the prescribed torque while following the bolt tightening sequence.

Newer manuals may have a different prescribed method.

Doc Frohmader had a good article on this, but I can't find it now.

Your right, only the rear cap has a positive locating method to install that cap. As for the others, you have to do the feel and scratch method with your finger or nail to get the caps aligned(crank removed). Once you get the cap located front to back, and side to side, you place some Dykem™ on the parting surface at where the cap faces meet the block and scribe an outline around the caps in question. Then once you install the crank, line up the scribe marks with the caps. Thats as close as you will ever get to aligning the caps with the crank installed, unless you dowel those caps as well.

I'm thinking the factory didn't hand fit every 235 or 261 they made.So it must be just like millions of routine rebuilds,just bolt it together.

Tony, I have no idea where I heard this or even if it is just something I imagined but, I seem to recall something about after the bottom end is assembled, loosen the main cap bolts, insert as this a feeler guage as possible between the cap and the piston rod next to it to keep the main cap from trying to rotate as the bolts were re-tightened.

keep em honest on the other thread. At least nobody has suggested velcro!

I just looked at a spare set of federal mogul mains, 2151 to 2154 for the late 55 to 62 motor. 2151,2 and 4 all have a dowel on one bearing shell and a tang on the other to locate the bearing. 2153 is the thrust bearing. I am not sure I have ever used bearings that did not have these locators. I have always stayed away from the early 55 and earlier blocks just to avoid messing with the shims. do these motors not have locators for the mains?

We're talking about the cast iron bearing caps,not the inserts

Silly boy that I am. Yes, no locators on the caps except for no 4