I've spun the 100% stock rotating assembly in the Malibu to 5500-6000. It's balanced of course, but I'm not sure how often I'll do that on a crank, rods and pistons that have 200,000 miles on them (oh yeah, a stock 2-bolt block too) :lol: I typically don't really push it past 5,000, just because it's on old stock parts. If I had new stuff that's been checked, forged rods, splayed caps, etc. I wouldn't hesitate to do it.
cast crank hits 6500 rpms
- Thread starter JOHNWOJO
- Start date
All you need to do is post the casting number which is cast into every cast or forged crankshaft and run it through google search you will have your answer. 
Jim
Oh add another to the 7000 cast spinning club 12.5 - 1 compression bracket racer... 6 years and running 355 small block.
JimOh add another to the 7000 cast spinning club 12.5 - 1 compression bracket racer... 6 years and running 355 small block.
You guys are making me feel a lot better about running a cast crank :lol: My only worry will be the caps on the block.
Ah...That is a 2 bolt main also.
Here is another good one for you. I had a totally balanced rotating assembly but when I assembled the motor I must have got some dirt in the oil passage it went straight top the crank bearing and scared the bearing surface which killed oil pressure.
Sooooo I removed it and since at that time money was tight...I replaced it with a STOCK .010 .010 ADVANCED AUTO of the shelf cast crank with bearings for 100.00 LOL.
THAT IS WHAT IS SPINNING 7000 RPM with 4.56 gears. lol. Oh boy... Tell you I really did not think it would hold either.
AGAIN this could be luck but I am taking what I can get. Jim
Here is another good one for you. I had a totally balanced rotating assembly but when I assembled the motor I must have got some dirt in the oil passage it went straight top the crank bearing and scared the bearing surface which killed oil pressure.
Sooooo I removed it and since at that time money was tight...I replaced it with a STOCK .010 .010 ADVANCED AUTO of the shelf cast crank with bearings for 100.00 LOL.
THAT IS WHAT IS SPINNING 7000 RPM with 4.56 gears. lol. Oh boy... Tell you I really did not think it would hold either.
AGAIN this could be luck but I am taking what I can get. Jim
Looks like a steel GM cank to me too.
I bet the dampner was bad, thats the usual suspect when a crank breaks.
Andy
I bet the dampner was bad, thats the usual suspect when a crank breaks.
Andy
im no expert but it looks cast to me, i spy a thin casting mark on it right by a main cap towards the top of the first picture.
Been shoveling 30 pounds of boost down the throat of a cast crank two bolt main. Those caps have walked to Mississippi and back, but it's still hangin. Not recommending, just smiling about it. I agree there was something on its way out there
Malibu355 said:
Yeah, what he said. I thought it was a cast crank too, by the thin part line. BTW, I spin all my cast cranks to 7000. Been doing it for umpteen years (not balanced). Nothing has come apart yet. Im talking, several 350's, destroked 400 to 377, all small blocks with no more than 11.7 to 1 compression. Even with nitrous.
I run a stock crank stock rods w arp bolts and sivolite claimer pistons.Have reved it to 7200.Dont do it any more because it slowed the car down.Ive also hit it numerous times with a 125 shot right off the line.Its been together for about 10 or so years except for rings and bearings.Oh still stock bolts in mains and heads.
