Ahh.... I see that you have the Flo's (?) small brake booster in there now

Looks
like you should have enough room for your filter. You want at least 25mm from
the inside of the foam to the mouth of the trumpet if you can manage that.
I'm going to take a guess at what happened with those wires. The OEM oil pressure
sensor is a bit of an odd one. It only has a single wire like a switch, but it actually
is a proper pressure sender. Only works with the OEM analog cluster IIRC. So it is
likely the guy who made the loom thought it was a switch and gave you that one
wire with the female spade so you use the "switch".
Then he figured you wanted an oil pressure input for the ECU/dash but didn't know
what sensor you were going to use, so gave you a standard Deutsch DTM3 male
connector instead of a plug. The idea would be that you make a small adapter cable
to join a female DTM3 to the plug that fits whatever oil pressure sender you choose.
So if you can identify the sender that is screwed into your block you should be able
to get a matching plug. Sender probably needs to be a 0-5V output type at a guess.
Your ECU file will tell you what a LINK analog input likes

Cheers... jondee86