Please can someone help me in identifying a 403 crankshaft from a 307 or 350? I got a machine shop guy drying to screw me!!

 

350 casting# = 393654
350 & 403 =558711
307 = 556607

Other than the early 350 being heavier, there shouldn't be any difference.

Norm

 

Thanks!! The crank the guy tried to give me had the #556607 on it. I know what my stuff looks like and that wasn't it. Is there a groove in the front counter weight on the 403? (along the length of the weight)

 

I'm guessing, you thought you were getting your own crank turned, when in reality you traded your core for a kit. As far as the crank grinder is concerned, there is no difference. He simply gave you a finished 3.385" Olds crankshaft, from off the shelf, so you wouldn't have to wait in line for yours to be machined.

Up to 500 (or so) HP I would have no problem using the 307 crank.

I'll leave that for someone who knows.

Norm

 

The reason I wanted my crank is to keep it as close to the internal balance as i could. It was a fresh rebuild that the guy ran it to fast to long that left no oil in the pan and all in the top. The rod and mains got a little lose after that. I got the car cuz he didn't want to mess with it so thought I would just turn the crank and put it back together. If it vibrated after I put it back together then I would redo the whole thing but am involved in a 455 install at the moment and didn't want two projects.

 

The reason doesn't matter.

Unless you are dealing directly with the Crank Guy (who will always ask) you need to tell the shop exactly what you want. If not, you will get what everyone else wants.

My way of saying: No one was trying to "screw you".

Norm

 

The whole story is that I am trading him a standard buick455 crank for him to turn mine and he said he would turn it and give me $35. When I go to pick it up he's not there so I figure I'm beet out of the $35. So I get the crank and start to leave and the guy that is there calls the guy i talked to and says I owe $35. I told him how I under stood him and told him I have to think about it and notice that the crank I got isn't mine so I start to just take my stuff and leave and then he wants to do the original deal. But he shows up after I am backing out the deal so he was just hiding in the back. He said he would fix everything so I left and when I get back to the shop I get uneasy about it. I call the guy and tell him to stop everything cuz I might not fix this motor and now all the sudden he has a good 403 crank where mine has a bad trust. He also told me that the crank I had was a 307.

 

Oh yea, my dad did a 403 build and used a 350 crank. To balance the crank the machine shop had to put mallory slugs in the counter weights. It was a 350 crank the machine shop was trying to give me. That thing would have vibrated real bad!!

 

So even if you try 3 different cranks the thing would still vibrate if the rods are junk.

 

Everything is still in good shape. No spun bearings or rod crank contact. Thats why I was just going to turn the crank and put it back together.