Oil Pickup Woes

[Runner 68]

I'm struggling with the oil pickup on this build. The block is a '76 400 that we are stroking to a 499.
This block was virgin. I didn't pay enough attention when I shucked it down. Now we're gearing up to put it back together. I assumed it had a 3/8 oil pickup which was too small, sent it back.
I figure somebody must have opened it up 1/2. Bought a 1/2 and it won't start either. The OD of the hole is ~.753 but I noticed the threads don't come all the way up to the edge of the hole. Not to mention they don't look like NTP to me.
Every block I have ever seen, they come all the way out. I'm stumped. What do I have here?

 

[Curiousyellow71]

Looks like someone started to drill it out for a 1/2" and didn't finish it or it was stripped.
Drill it out with the proper size drill bit and buy a 1/2" pipe thread tap. Take your time doing it and it will be fine. I would guess a 3/8" pickup will no longer work.

 

[Runner 68]

Thanks. I wish I would have kept the old pickup and paid closer attention. I wonder now what exactly was in there.
The threads at the bottom are not 3/8. It's wierd.
I'll have my machinist tap it out if that's what it needs. I won't touch it.

 

[Lefty71]

I'm not really seeing threads at all. Truck block?? I wonder if there was a studded main bolt in your collection of parts??

 

[Runner 68]

I'm not really seeing threads at all. Truck block?? I wonder if there was a studded main bolt in your collection of parts??

Threads are down in there just hard to see in that picture. No studded main bolt. Pretty sure it is a car block. I think the main difference between the two was rear sump (Truck) and mid sump (Car) and cam. I realize the pickups will be different but not where they thread into the block. Curiousyellow's theory above so far seems to be the most viable at this point.

 

[69Bee]

Someone did not finish going to 1/2"NPT. The inner/outer NPT hole size for 3/8" NPT is 0.612"/0.675" and for 1/2"NPT is 0.758"/0.840". You have two choices:
1) Install a Time-sert Pipe Insert for 3/8"NPT ($220)
2) Get a 23/32" drill and 1/2"NPT Tap and finish job already started (Less than $220 probably)

www.threaddoctor.com/time-sert-0318-3-8-18-inch-taper-pipe-thread-repair-kit

 

[moparedtn]

Machine shop will get you squared away, no worries.
Might be a good idea to bring the new 1/2" pickup with you when you go there.

 

[Runner 68]

You mean like the one below?
My only concern is that smooth part may be too big to tap. My shitty micrometer measures it at .753. For 1/2 NPT I read that the hole should be .719.

 

[moparedtn]

You mean like the one below?
My only concern is that smooth part may be too big to tap. My shitty micrometer measures it at .753. For 1/2 NPT I read that the hole should be .719.

View attachment 1348971

Preferably the 1/2" pickup you're going to use, sure.
The machinist will no doubt do some measuring on the block - but on that pickup too, just to be safe.
Let him tell you about any issues with the block. Don't assume.

 

[69Bee]

You mean like the one below?
My only concern is that smooth part may be too big to tap. My shitty micrometer measures it at .753. For 1/2 NPT I read that the hole should be .719.

View attachment 1348971

Re-read post #6, I gave you the sizes for the pipe tap holes. As long as your pickup is 1/2"NPT, you will be fine to tap it

 

[Runner 68]

Re-read post #6, I gave you the sizes for the pipe tap holes. As long as your pickup is 1/2"NPT, you will be fine to tap it

Sorry 69, your response snuck in while I was offline. Option two looks like the way to go. I just got off the phone with my machinist he said "bring her on down".
And yes, that is the pickup I'll use. Too much brain damage and $$$ hunting that [email protected] down. It's supposed to fit the 70-71 6 qt Hemi pan. Not returning it now.

What still confounds me is that the threads that are there are bigger than stock 3/8. Tried that first.

 

[zyzzyx]

Idon't know how to put a link to one of my posts, but you can search my content with the date October 13, 2020
titled 1/2" oil pickup Modification for our 440's. You might as well do the mod the right way since you're in there!
I'm sorry that I don't know where the Red Anvil Dog House is at, but you can borrow the fixture and tooling if you
need to!

 

[Runner 68]

Idon't know how to put a link to one of my posts, but you can search my content with the date October 13, 2020
titled 1/2" oil pickup Modification for our 440's. You might as well do the mod the right way since you're in there!
I'm sorry that I don't know where the Red Anvil Dog House is at, but you can borrow the fixture and tooling if you
need to!

Thanks for the offer zyzzyx. The dog house is in Colorado. A bit of a commute to IL.
My machinist has it covered. Will drop it off tomorrow with him.

I'm still confounded thinking about who and why they did what they did to this block.
I'll just let it go and fix it.

Thanks for all the input everyone. Good 'ol FBBO rapid response team.