my teacher built a 327 chevy and bored it out .060 on a non thick block. not long after building it the cast crank cracked in half. could this have been caused by the too much overbore? i was thinking teh pictons could have been dancing around the bores and this caused the rods to bind.

 

What exactly do you mean by a 'non thick block'? Most of the old 327 blocks would take a .060 overbore easily. I'd say that there are far too many things that could have happened to the crank and the overbore is the least likely culprit in my opinion.
Maybe the crank had a fracture in it... maybe it had too much runout... maybe the clearances were off in one or more main registers... maybe a spun bearing caused it too break... maybe, maybe, maybe.....

-Mindgame

 

327s are notorious as high spinning engines. Since cast cranks are not the best choice for a high RPM motor, that is certainly one scenario. Like mindgame said..always plenty of maybes.

 

The crank only cracked due to a flaw in the casting, long term fatigue or very serious HP. Unless there was a bearing failure as well...then something else probably caused it.

I used to work with 327's in 2 of my Nova's a few years back & they are very durable.

2 bolt main, cast crank, stock rods with ARP bolts & TRW forged pistons were the only bottom end mods.

You do not have to spend the big $$ to go fast, but if it does break you cannot be mad about it.

Top end had ported Brodix heads, Victor jr, 750 holley & 200 shot of nitrous. Shifted at 7200 1-2 & 7400 2-3. Daily driver with 4.56 gears... 4000rpm on the highway. Went low 11's on street tires, through the mufflers on pump gas. Never had a crank problem, but the main caps were starting to walk a little (borderline 4-bolt main required) main studs may have worked as well. Freshened it twice in 4 years. Only problem was squeezing the ringlands on TRW pistons once when I got too timing happy with this combo.