can u see the difference between the eagle, and the stock gm? nice huh?

 

holly ballanceing holes batman ...wow for some reason I woulden't feel safe using that GM crank with all those holes in it, it's a good thing you got that eagle crank, it looks good

 

looks very nice!

 

Makes me hungry for a subway #6 with Swiss.

 

I don't think I'd be blaming the General on that...the .010 grind on the crank would lead me to belive it was done during the last rebuild on the engine.

 

im not blaming the G' in general, but more just the looks of iron vs steel , and the casting difference around the half moons.

 

That crank definitely has a history.
So that is the crank that came in a used block from the junkyard?
It looks like maybe it's been welded on the journals.
If you wanted to do a bunch of detective work, you could prolly figure out how it got to be the way it is.
But why bother.
I'll have to admit it makes me scratch my head tho.

Did those rods and pistons come out of the old one, or are they your new ones.

 

the rods and pistons came out of the same block as that pos crank. it was purchased as a complete rotating assembly 383. everything except the crank looked fine.

 

Those might even be 6" rods with a forged piston. In which case the pistons would be a lot lighter than the factory parts that the GM 4-3/4" stroke crank was originally balanced for.
Even if they're 5.7" rods the 4" bore forged pistons would still be considerably lighter.
That would explain all the balancing holes.

Compare the weight diff of a 4" bore forged piston to a stock 4.125" cast piston. You'll see why a lot of rebalancing would be needed to make it right, with a factory stroker crank.

They're definitely aftermarket rods.

 

The pic's I saw are either 6inch rods or longer (maybe Ford l6rods?) as evident by the wristpin location to the oil control ring.

Was that the "modified" crank from the block you bought, or waht was in your car that you grenaded?

 

I've been getting that he bought a stroker from the junkyard.
The more I look at it, the more it looks like the block has been clearanced for a stroker crank. That is, if the orange block is the one that the "holey" crank came out of.
And it's hard to tell for sure but that crank has some grinding done to it on the crank throws, and it sort of looks like there's some welding bead showing there.
It would be interesting to find out what the actual stroke of the crank is.
Is it a 1pc seal crank?
Maybe it's a 3.5" stroke crank that's been welded to increase the stroke.
Or maybe a 3.75" stroke crank that's been welded for a longer stroke???

It seems like something NOT to throw in the trash.
If there are no spun bearings, it could be used again, mebbe.
And if the pistons were replaced with some that are equal weight, it would be balanced as well as it was originally.

 

Ya, on the West Coast Board, IIRC, he mentioned buying a 383, but said carnk was modified for the stroke, could have had the journals moved (lotsa work) or offsett ground like they used to do back in the day...who knows. I was just curious if it was the crank from his motor, or the one he bought.

 

It looks like a 1pc seal.
Possibly someone welded it up and offcenter ground it for a longer stroke, back in the 80s before 1pc stroker cranks were available as cheap as they are today.
It seems reasonable for a project back then.
It would have been one of the few hyd roller 383s back then.
A lot of work, but if the builder worked in a machine shop, it would have been a nice after hours project.

 

Interesting... it does look offset ground.

 

it was a crank that came in the motor i bought. on top of the crank they had this written on it "4.766" 10/10

so it probably does have alonger stroke then stock?

also, those are 6" forged rods that came with the block, and those are kb hyp pistons.

 

Looks that way. Spacing around those rod journals doesnt look like stock to me but sure way is to measure it. 10/10 would be rods+mains .010 undersized, not sure what the 4.766 is. Vaguely familiar but I cant recall. Maybe part of the casting number.

 

Could they have meant 3.766 and the increased stroke?

If this started as a factory 400 crank then offset grinding would produce a stroke right around that number.

 

Look close (3rd pic), thats a one piece rear main crank. Pretty sure there wasnt a way to turn a two piece into a one piece.

 

correct so i dont know how they got a stroker crank out of a gm crank?

 

Maybe it's not a GM crank. Why not just measure the stroke on it.
Lay it back in the block and use a digital caliper.

 

i dont care enough

thier is a big square with GM printed inside. im pretty confident its a gm product.