RB 440 oil thread size

[Cato Vinther]

Hey.

Somebody that knows the thread size for oil sender/switch holes? there are two diffrent sizes.
I've mountet a oil press sender in the small hole, and want to mount a oil press switch in the big hole to make some engine cut off system.
What size thread?
and what PSI should i buy for cutoff, 10 psi?

Br Cato

 

[IQ52]

1/4" IPS (iron pipe size)

 

[Mopars & Missiles]

Funny, mine have all been 1/8" NPT

 

[rbbruno3]

Funny, mine have all been 1/8" NPT

Thats what I was thinking

 

[DetMatt1]

There are 2 different sizes back there. My Imperial uses both because it has a light and a gauge and the switches/senders don’t interchange.

 

[Mopars & Missiles]

So what engines/applications have the 2 sizes? My RB's (440's & 383's) all have the 1/8" NPT if I recall correctly. Yes, two ports into the oil galleries but I think their both the same size on mine. My engines are from '69/'70 B and E bodies, so maybe they were different in earlier years or the larger platform cars?? Now I'll have to go out and recheck those plug sizes.

 

[DetMatt1]

My Imp is a ‘67 440 and this is the 440 out of my ‘68 R/T.

 

[rbbruno3]

You are right IQ52 and Matt . Checked all the blocks I have there are 2. 1/8 and 1/4

 

[Mopars & Missiles]

Time for me to "eat crow". I am WRONG and of course the others are correct.

Here's one of my '69's. Its a 440, Has HEX pipe plug in the larger port. Obviously 1/4" NPT.

Here is a '70 383. Has an ALLEN head pipe plug and is deceptively smaller looking, although closer look confirms it is 1/4" NPT also.

Here's a '69 383, and again it has the HEX pipe plug. Much more noticeable that it is larger.

Lastly, here is a '75 400. Once again, it has the ALLEN head pipe plug that LOOKS smaller at first glance.

Looking back on things, the two engines with the ALLEN head plugs are the most recent engines I've built. I used the same machinist on both of those blocks and I'll bet that's how the allen head plugs in those came about. The other two with the HEX head plugs are most likely factory style plugs, as those have not been messed with in over 35 years. SO........

I would like to sincerely say "I'm SORRY" for the mis-information I first posted. I did not intend to mislead anyone and obviously thought I remembered correctly, but I did NOT. Old age is creeping up on me and it is starting to scare me now.

Thank you DetMatt and IQ52 for setting me straight.

 

[DetMatt1]

No worries man!