454 or something else?? 496??

[6600DURAMAX]

Posted this in the general section but thought it might be better here since all of you deal with this stuff daily.

Bought the truck over a year ago and was told it was a 468 (bored 454) the current owner didnt know much more that that.
Found out by pulling the vavle covers early on that it has a set of Mid-Lift Roller Rockers along with a roller cam and lifter....... was pretty excited about that. Obviously could pull the pan without pulling the motor and everything was in to good of shape to do that................unitl now

Well below are some pics of what I found today.

MY QUESTIONS ARE AS FOLLOWS:

1. Is this a 454 or is it a 496 (probably dreaming or wishful thinking but follow me on this)

2.. I know they are H beam rods but I cannot find any part numbers to determine the length, from the center pin to the center of the cap they measure around 6 3/8'' (kind of hard to get an exact measurement) Why isn't there a part number? Is there a correct way to measure the length while in the block??

3. Crank?? Obviously an aftermarket but again can find no part numbers. Is it a 4'' stroke or a 4.25 stoke? How in the world can I tell without pulling the heads? Look how close the crankshaft is to the block? Can I tell if the crank is cast or forged by looking at the flywheel end?

4. The flywheel did not have a weight on it??? Should have for an externally balbnced 454. Maybe it is a forged crank that is internally balanced (probably wishful thinking again.


Help me out here guys this is driving me crazy.

Oh ya Bad news of today was the MSD distributor gear has 4 or 5 teeth that have worn to a knife like point What causes this?

MSD looks like it is corroded beyond belief, dont know how it even ran? What causes this?

And the las tbit of bad news/good news is the oil pump pickup was broke of and bairly hanging on?

I know this is long post but any help would be appriciated