Does anyone recognize these pistons and rod bolts.

[N2BUICK]

Still trying to find out more about this 4.1 short block.
Does anyone recognize these pistons?
The rod bolts, are marked BPG. did Buick Parts Group have their own branded engine parts?
Can anyone say the bored out hole in the front crankshaft front are something for machining or was metal removed for balance?

 

[750H.P.V6]

The pistons appear to be a .040" over cast piston, not sure of the brand. The drilled hole in the counterweight is where material was removed to balance the rotating assembly.

Neal

 

[N2BUICK]

Neal, thanks for information. I had seen cranks with that kind of hole in the past but never thought it was for balance. I thought being so close to the center line it would not have very much affect on balance?
Do you have any thoughts on the BPG rod bolts?

 

[750H.P.V6]

The hole I was referring to was the one in the counter weight. The hole in the rod journal is a bit weird as it appears to be a stock crank. I have seen this done in aftermarket forged cranks to lighten the rotating assembly. As far as the rod bolts go, I blew up the pic and couldn't make out the lettering that well. Are you sure its not SPS? They look like stock rods and rod bolts.

Neal

 

[N2BUICK]

Yes I was giving up on getting any traction on BPG. Eye sight doesn't get better with age, thanks