Nice!   Looks familiar.   

In measuring a ARP shaft I have sitting here, the diameter at its middle is 0.370” while the pilot hole for the distributor is 0.450”.  That means the shaft without any kind of retention washer (AKA star washer) will come up (or fall down) through the distributor hole.

TED,
Any chance of getting the length on the ARP shaft?
THANX!

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tbirddragracer,   Ernie, that black  57 bird is the nicest one I have ever seen, although not stock. the pictures of your car do not do it justice, it has to be seen in person. love that car . hope to stop in next time I am down in Mineola.----  Jim

The two ARP shafts I have sitting here both measure 8.070” for their overall lengths.
 
Going through my parts bin, I found 23 used Y-Block oil shafts and they range in measurement from 7.990” to 8.090” with a good number of them being around the 8.070” number.  There were enough of those at 7.990” though to realize that they were a legitimate low end number and not an anomaly.

Lorena, Texas (South of Waco)

The two ARP shafts I have sitting here both measure 8.070” for their overall lengths.

TED, again appreciated. I know you are a bust man.

So the change to rotor style pump was in mid/1956 production? That explains a lot. Wish I had all of the PRODUCT SERVICE LETTERS of the period.

BTW - I found the advertised length spec on MELLINGS IS-42 Shaft - 8.06" L if anyone needs the info.

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7 Pages for a washer has to be a record

7 Pages for a washer has to be a record

It is not a washer so much as intermediate shaft length difference(s) that can lead to a serious problem(s).

An engine is only as good as its' assembly..

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I found this post slightly informative but incredibly entertaining.🤨

I just threw up in my mouth! 
PLEASE STOP!

"FREE SAMPLE"

it started as a washer and went everywhere