Thread: 350 rebuild questions

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Hi all,
I have a 75 K10 with a 350 that I have pulled with the intention of rebuilding. On pulling it apart I find the attached number and logo on the rod and main bearings. I figured that the 010 means and oversized bearing but the same logo and number is stamped on the bearing caps which didn't make sense to me.

If you turn the crank and use oversize bearings to compensate what does that have to do with the cap? I would think the cap would be unchanged unless someone align bored them.

Does anyone recognize the logo? I want to be sure it's not a part number before I order oversize bearings. I may end up replacing the crank as I have heard of failures on turned cranks but want to be sure I can drop in a stock one without problems but the cap stamp is bothering me.

I don't have the history of this truck. I bought it from a kid who didn't know much about it. The block is a 4 bolt and according to the casting numbers it's a cast crank, lightweight (crack prone) heads. It’s been rebuilt before. Felpro gaskets and "20" on the pistons.

I also had broken rings on the 2 front most cylinders. They were the number 2 rings. Does anyone know why those would break before the number ones? All I can think of is improper install.

The left rear piston is all beat up from a foreign object. The cylinders are in surprisingly good shape after all of that.

Any info would be appreciated.

Thanks

Mike

It's been built before so don't take chances and take the mic to everything!!!!

Mike,like Dave told you to mic everything.The way cylinders "look" is kind of meaningless.From what your describing,sometimes you much better off finding a virgin seasoned engine and build that.

iron gm cranks do not break from getting turned down .you can not cut a stock crank that much to weaken it for stock use less you grind the radius out of the crank . rods they started using a over size housing bore rod bearing for the fractured cap rods were they can not be cut to shink the housing bore and hone back to size . some rebuilders can use this bearing on the older gm rods to save a hurt older rod. i do not know of any over size housing bore main bearings but some one may make them . if the # 5 main cap is stamp then it could be 010 over on the crank thrust or somone just stamp 010 on the cap stating that the line bore was moved that much. rings breaking . ring gap to small . not handled right . engine tune up off . i seen that makers mark on bearing before many times . it is the vanderevell bearing now the mahle/clevite /vanderevell owned by mahle