So I have two standard pressure oil pumps I plan to use on a future build, and I want to modify them for better flow. I just have a few questions before I get into them.
#1 seems pretty straight forward, drill the neck from the main cap to the internal rotors to 1/2" and then clean the passage up with a sandpaper roll.

#2 would it be beneficial to smooth the ridge from the pump body to the rotors with the sandpaper roll? Picture with area of interest circled in red.
Should I remove the bypass? How do you get them out?
Any other tips?

You can do what you are asking as I think any little bit helps.

The real issue for these types of pump (gerotor) is the inlet (suction) side of the pump can NEVER be too big. You will gain more working on the suction side of the pump.

I'm building my personal street engine right now and I'm mentally masturbationg over making it a dual pickup pump. I prolly won't but I'm as hard headed as it gets and I keep looking at the pump and the voices in my head say "do it...do it...you know you will HATE yourself if you don't".

So I may not do the dual suction thing but I might. I definately have a big inlet. I think it's 7/8 ID.

Guess I could measure it.

You dont have to go crazy on the inlet... the engineers
at Chrysler did their homework and testing... I've run a
SB to 8200 rpm for years with a totally stock pump and its
still running today... now days I blend in the ports and
smooth them out.. I bend my own pick up tubes with a thinner
wall so it has a larger ID
EDIT
I do drill the oil holes in the block as done in the
books

Well then I guess we know different engineers, because every single one of them says (and have done the testing) that you can't get too much area on the inlet side of the pump.

Now add a taller rotor and scroll ("high volume" although I have never found out who determines what "high volume" really is) and you work the inlet side even harder.

It's simple hydraulics really.

Make the inlet as big as possible. The pressure side will take care of itself (within reason).

Well then I guess we know different engineers, because every single one of them says (and have done the testing) that you can't get too much area on the inlet side of the pump.

Now add a taller rotor and scroll ("high volume" although I have never found out who determines what "high volume" really is) and you work the inlet side even harder.

It's simple hydraulics really.

Make the inlet as big as possible. The pressure side will take care of itself (within reason). [/quote]

Yes the larger the inlet keep the negative pressure better
but you still dont have to go crazy... I use either the standarde
or HV pumps depending on my clearances... on my 416 with lots
of extra leaks(as in EDM lifter holes and .003 clearances on
both rods and mains and PR oiling).. and I check the by-pass
on the pump to make sure where it starts to by-pass).. this
gives me 18#-20# oil pressure hot at idle.. and I do
know hydraulics.. thats what I went to school for
Remember that its the atmospheric pressure thats
pushing in the oil... the pump just creates the negative
pressure... just like the cylinder does for the engine..
and if you run mud in the pan it makes it harder to push

Yes the larger the inlet keep the negative pressure better
but you still dont have to go crazy... I use either the standarde
or HV pumps depending on my clearances... on my 416 with lots
of extra leaks(as in EDM lifter holes and .003 clearances on
both rods and mains and PR oiling).. and I check the by-pass
on the pump to make sure where it starts to by-pass).. this
gives me 18#-20# oil pressure hot at idle.. and I do
know hydraulics.. thats what I went to school for


IMHO, as one of my professors said, is "there's good, and there's good enough". MR.P, you have way more experience with this than I do and if it works for you, then I'm drinking the kool aid.

That said, my set up is an NOS Direct Connection kit with the Penstar shaped bottom inlet cover. This thing takes 3/4" NPT! Might be overkill, but it makes me feel good.

I just edited my post.. but... you have to remember that
the pump creates the negative pressure so the atmospheric
pressure can push in the oil... its much easier with thin
oil over mud.... no different than the cylinder on the engine

Right, the oil pumps fuctions because of pressure differential.

The guys who are screwed are the ones who use a mid sump deep pan, with a long pick up tube that is stock diameter. They don't have near enough area in the pick up, even if using a 20 grade oil. And then add a higher volume oil pump (like I said) and you start seeing top end oil issues, fluctuating oil pressure and the like.

Dont radius the edges in the pump gear housing. You can smooth out the passages internally, but the holes are "timed" to the gear/rotor, and if you radius the surface, you will mostlikely lose pressure, or have difficulty with priming on hot starts.

Ok, thanks for the heads up on not radiusing the body.