I put in new coated cam bearings yesterday and the #4 bearing was stiff on the cam when turning, and the #5 just wont let the cam go in. I googled it this morning and read that bbc bearings have different OD i also read other posts that said they don't. I think i just wasted 60 bucks on bearings but I'm hoping it was due to my ignorance and not the block. I looked here first but couldnt find anything addressing this. Could someone get me smarter on the cam bearing diameters? I used a coated durabond bearing set from summit; i saw some numbers on the bearings but they looked like production numbers. The motor is a mk IV 454. Brand new cam Thanks Charlie
Big block Mark IV engines use different size OD cam bearings, just like small blocks. No.1 is the largest OD. 2-5 then 3-4. The numbers on the back of the bearing usually have a -number that determines the position of the bearing. Also the bearing box has bearing number position printed on the inner flap.
Its been awhile since my original post but since then i took the block to a machine shop (s&s in san leandro) and they said the #4 and #5 journals for the cam bearings are undersize. Anyone heard of this before? They said to turn the bearings down and install normally.
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