Hypereutectic pistons and failures related..

dodge freak said

.028 is still "tight" for K.B.

Check out their guild for ring gaps.

For Circle Track - Unrestricted .0080" per inch so a stock 360 bore should be .032

For Marine - Normally Aspirated .0080" -same gap as Circle Track

Street - Towing is .0080"

I don't know why they say for Street - Normally Aspirated .0065", guess that is for "normal" people. (those are the ones in the far right lanes on the freeway we go zipping past, ha ha)

The Wall Clearance is what really changes. Goes from Street - Normally Aspirated .0015" - .0020". Circle Track is .0030" - .0045". Marine .0030" - .0045"

Why Marine use is so much higher than "normal street use" IDK but like I said, we aren't "normal street" I guess.

I am asking for min Marine spec's (good point if the shop will listen thou)

KB Pistons for Automotive Applications:
http://www.kb-silvolite.com/kb_car/clearance_pop.php

Click to expand...

My 340 w/KB243's has .029 top ring gap, 7000rpm and no issue.
I've run KB's at .008 just teetering in the bore, besides noise, no issue.

I've only scuffed no.5 in a 340 before with the kb's due to spark jump/cap& rotor phasing, once I changed the distributor & sleeved the hole..no issue.

as for the finish...I run your basic hastings single moly top rings.

I tell you this....this is the 1st block I have had done at this shop....
I'm thinking it's the last as well, I might go back to hds or ricks machine in sante, though the customer service guy is a douche bag...at least rick does excellent work and has family generations in experience.

I have not had a chance to speak with Brian yet, but will and 1st consider his shop before making a move.
It just sux that he is an 1 1/2 away.

I was thinking too tight a wall moper, cause theres no sufficient oil there, thats a lot more swept and side thrust. jmo
But I am all ears to any idea's and thank you all giving them.