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matter of fitness...LOL

Sorry for the pun. I would imagine that the intended use, RPM level of the engine is a major concern. If your going to run around and see an ocassional 6K, Clevlites were used by GM for yrs. & yrs. Back in the day when folks got 100K or so on a engine without any bearing issues at all. Of course more importantly is the oil clearance specs. Nothing is going to hold up for very long if those specs aren't 100% correct for the useage intended. GM designers were not dummies back in 40-50-60's. They built a product that was intended to last. The consumers would not accept anything less. Hence all the hand me down cars to the kids after they graduated high school etc. From mid 70's until today, all vehicles have been considered to be disposable. They are NOT designed to last like the older ones. For a 'normal' rebuild such as a 350 CID in the OEM 350 HP format or any other SBC I would get one of the better SBC Engine rebuild books and follow what was really used back in the day {so to speak}. You'll find that even with a true 350 cid -350 hp cast, press pin, pistons were used, cast crankshafts, its the stuff you can pick up CHEAP and is extremely useable. Of course if your going over 6K RPM on a regular basis, tend to lean towards the forged stuff. Spend the extra for a descent oil pump, something thats already been deburred and perhaps blueprinted, and do NOT make the mistake most folks do. Install your oil pump, and drive rod, put a cple. bolts in your intake [with gskt], install your dist {with gskt} and then flip the engine over on the stand. IF you hear the oil pump shaft dropping back and forth you NEED to correct that ! DO NOT leave it with too much clearance, its a VERY common mistake ! IF you have too much clearance and are useing a OEM style pump your going to have to remove the plate from the pump, and press the shaft that goes threw the gear and aligns with the oil pump driveshaft. Making the shaft in the pump in essence longer to take up the extra clearance it needs. Your only supposed to have about .060 + - .020 clearance. You would be extremely surprised how many engines get built without this issue being addressed & corrected if at all. If it's too tight simply grind/file off the rod until desired clearance is achieved. I know you asked about bearings. But do not forget about the essentials either. Block align bored ? ALL crankshaft journals micced ? Even brand new crankshafts you'll find have lumpy journals, flat spots, oil hole chamfer holes too large and screwed up countersinks, radius edges are on too much or too less of an advertised degree {usually .125} and just outright smaller/larger journals by .001 or so. Last but not least ck. your thrust clearance. Remember, the oiling system is the heart of longivity. No bearing is able to correct that on its own. Junk in....expect Junk out. Meaning poor performance, 20K miles later & its knocking etc. So in short if all your bearing clearance are right on the money, your thrust is right, any of the main mfgs. bearing will suit your needs perfectly. It wouldn't hurt to use a full groove main brg. set ! Sorry to have rambled I hope its helped in some way.
 

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Sorry for the pun. I would imagine that the intended use, RPM level of the engine is a major concern. If your going to run around and see an ocassional 6K, Clevlites were used by GM for yrs. & yrs. Back in the day when folks got 100K or so on a engine without any bearing issues at all. Of course more importantly is the oil clearance specs. Nothing is going to hold up for very long if those specs aren't 100% correct for the useage intended. GM designers were not dummies back in 40-50-60's. They built a product that was intended to last. The consumers would not accept anything less. Hence all the hand me down cars to the kids after they graduated high school etc. From mid 70's until today, all vehicles have been considered to be disposable. They are NOT designed to last like the older ones. For a 'normal' rebuild such as a 350 CID in the OEM 350 HP format or any other SBC I would get one of the better SBC Engine rebuild books and follow what was really used back in the day {so to speak}. You'll find that even with a true 350 cid -350 hp cast, press pin, pistons were used, cast crankshafts, its the stuff you can pick up CHEAP and is extremely useable. Of course if your going over 6K RPM on a regular basis, tend to lean towards the forged stuff. Spend the extra for a descent oil pump, something thats already been deburred and perhaps blueprinted, and do NOT make the mistake most folks do. Install your oil pump, and drive rod, put a cple. bolts in your intake [with gskt], install your dist {with gskt} and then flip the engine over on the stand. IF you hear the oil pump shaft dropping back and forth you NEED to correct that ! DO NOT leave it with too much clearance, its a VERY common mistake ! IF you have too much clearance and are useing a OEM style pump your going to have to remove the plate from the pump, and press the shaft that goes threw the gear and aligns with the oil pump driveshaft. Making the shaft in the pump in essence longer to take up the extra clearance it needs. Your only supposed to have about .060 + - .020 clearance. You would be extremely surprised how many engines get built without this issue being addressed & corrected if at all. If it's too tight simply grind/file off the rod until desired clearance is achieved. I know you asked about bearings. But do not forget about the essentials either. Block align bored ? ALL crankshaft journals micced ? Even brand new crankshafts you'll find have lumpy journals, flat spots, oil hole chamfer holes too large and screwed up countersinks, radius edges are on too much or too less of an advertised degree {usually .125} and just outright smaller/larger journals by .001 or so. Last but not least ck. your thrust clearance. Remember, the oiling system is the heart of longivity. No bearing is able to correct that on its own. Junk in....expect Junk out. Meaning poor performance, 20K miles later & its knocking etc. So in short if all your bearing clearance are right on the money, your thrust is right, any of the main mfgs. bearing will suit your needs perfectly. It wouldn't hurt to use a full groove main brg. set ! Sorry to have rambled I hope its helped in some way.

Nice second post (or it could be your first...)! Welcome to Steve's!
 
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