What are the clearances for the mains and rods in a 455 pontiac? also, how do you go about mic-ing them? thanks

 

Going by the .0011 x journal diameter rule that makes the clearance to shoot for .0035.

You gotta measure the journals, then set the bore guage to that journal size, set the bearings in the block, TQ down the caps and see what your clearance is.... repeat and change bearing shells till ya get it right.

Bret

 

For a street car shoot for .002 on both. A race car can have .0025-.003 depending on max rpm. I had my crank reground to reduce it from .0035 to .002 and I've run mine up to 7200 rpm.

 

I'm assuring you went .010 or so under so you could use .010 under bearings. Just grinding the crank .0015 increases the clearance.

You spin a 3.25 main Poncho regularly to 7200 with .002 main clearance? If so, you are lucky.

 

Wow.

Keep on running at .002" and you are going to gain some babbitt/steel welding experiance.