What is a offset ground crank?I have a 451 that im putting back together from a failed lifter..and where they turned down the rod journals it goes straight across throw to throw not beveled at the edges is that normal for a turned down crank?The rods have been rubbing the edges of the counter weights slightly and i am unsure if this is right..and the rods gap.030 between..oil pressure was 80psi Is this a 440 crank or 400 crank..I am new to this stroker engines buisness and am having to learn on the fly here.
Also why do some call it a 452 as well.My crank has that wrote on one of the counter weights with a sharpie.
Mains are standard and rods journals turned .020.

Basicaly need answers on the crank issues and love to have links to anything 451..Thanks so much....

Looks like what you have is a cut down stock 440 crank , that is why the mains are standard . The mains on a low deck are .125 smaller than the RB so it's a way to save an otherwise trashed 440 crank .

The cut down 440 crankshaft program was a cheaper way to go before the advent of the Chinese imports.
To answer the original question about offset grinding, This was also a way to gain stroke on the cheap. I remember hearing about it in the 80s. I'm sure that it was done long before that though. The rod journals are ground in a matter where the center of the journal is moved. In some cases, the area of the journal at bottom dead center has been built up by welding, then the entire journal is machined to standard size. In other cases, only the top edge of the rod journal is cut and the builder used rods with a smaller journal size.

Thanks guys..so with the 440 crank is my engine internally balanced now?Lot of balancing work done to this.Thanks again.

As far as balancing, look at the counterweights. To use a 440 crank in the low deck blocks, the counterweights have to be shaved down to fit. I would HOPE that the machinist also drilled and/or plugged the crank for balancing while he had it. If not, the balance factor would be different than a stock 440 and be more difficult to compensate at the flywheel and dampner.

Great to hear you're going through the motor and doing this right.

Your crank being cut straight across as you have described is normally just fine, but if the rods are truly rubbing on the counterweights, that could be a problem, and would seem very odd. Are you sure you mean the counterweights and not just the journal arms? Pics would be useful here.

Your crank is a 440, or RB crank (could be a 413 or 426). 452 vs. 451 is just an overbore measurement. My motor is .040 over, and displaces 452 cubes. A .030 over 400 block makes 451 cubes. Same motor.

Offset grinding is hard to describe, one picture would make it clear. Immagine a cross section view of the cranks rod journal. If you were to grind the journal down to a smaller size, and take all of the removed material off of one side of the journal, you would move the centerline of the journal. Move it to the outside, and you've increased the cranks stroke.

Thanks for the great explaination on the offset.Thats crazy stuff.Yeah no new pics but you can see a little of the machine shop drilling in the one pic.Car was extremely well balanced by "floorboard" feel..was just getting my head wrapped around everything as i tore it down....jus like you guys said,impellers had lifter meat imbedded and the main bearing but it never made it to the rods at all.Plenty of balancing on crank and rods.I never "act" like i know anything.Point being i have done alot of stock engine rebuilding in my life but this one makes me a little nervous because its my first b r/b and a exotic(to me) to boot!Been a MoPar guy since i was 17 (19 years!) first rebuild was a 360 at 17.The one guy i went to for answers never told me bout the external balancing because it was going where a 318 was in my old 70 Swinger.Shook like h*ll..he laughed and toldme the the deal after the fact..he said he knew i was serious bout my transformation from Chevy to Mopar and after this i would never make the mistake again.He was right!!Sorry for the

You don't really gain a lot of stroke by offset grinding but one thing you can do nicely with it is the added stroke will bring the piston further up in the hole. You can gain a few cubes and some compression without having to mill the snot out of the block's deck.