440 Block Machining for 1/2 Hemi Oil Pick-up

[john108]

I plan on having my 440 Block Machined to accept the 1/2 Hemi Oil Pick-up.
I know I have seen info here but couldn't find what I was looking for.

Other than machining the fitting, in the block, to accept the larger thread: What passages have to be enlarged and how are they accessed??
One post I did find had the threads machined slightly off center to center it within the material.

I also remember reading that there was a concern that if a certain passage was increased in size, some oil pressure and flow would be lost to the heads (if I remember correctly but probably not!).

Thank you again to those with a better memory than mine or who just know the answer. - John

[heyoldguy]

Hello John,

Machine the block for the 1/2" pickup if you wish, but I have found it to be superfluous. The old 500 stroker uses the 3/8" pickup, winds 7600 rpm, makes 928 HP and never loses oil pressure.

[John_Kunkel]

Other than the expense and hassle, there is no downside to enlarging the pickup size as long as there is sufficient meat on the block boss (some are too thin there). The size of the pickup won't have any effect on the passages downstream.

Once the hole is enlarged I like to use a rotary burr to round off the sharp corner where the pickup hole transitions to the pump feed passage...the transition angle is over 90° and the sharp corner presents a flow restriction.

[john108]

Then it appears that there is no need to enlarge the pump discharge passage going through the length of the block??
I thought I remembered reading that someone did machine the passage and accessed it through a plug at the rear of the block.