I just got home from the speed shop, got to looking over some new parts. Looked at the package for the moroso oil pump drive shaft and it said machining was required for a 400 sbc. What is up with this?

 

400 oil pump shafts are necked to clear the crank.

 

So I need a 400-specific oil pump drive... great. I guess i've never even seen one.

 

Melling IS-55E

Miloden makes one as well (I use the Miloden one).

 

Since the 400 shaft works in all the other blocks as well, most of the aftermarket shafts are similarly clearanced. I'm surprised the Moroso one isn't?

 

I was suprised when I saw that too, but sure enough, its not necked down at all.

Now that I think about it, the priming shaft i have is also just straight with no neck down... I hope I can prime the motor and turn it over a couple times while I'm doing so.

 

That won't matter, the priming shaft replaces the distributor, not the oil pump driveshaft.

 

LOL... its amazing the things you forget in a year, that'll teach me to say something before I think about it.