Injector Insulator

Just picked up a set of new injector insulators but I dont believe they are sealing properly

How snug are they supposed to be to the injector?
The old crusty ones are tight against the injector, but the new ones seem to be loose.

They are supposed to be tight against the injector are they not?

They shouldn't be loose, they should fit relatively snug, snug enough that they will stay on the injector end often when you pull them out.

Thats what I thought, but these are OEM injectors from Mitsu.

Do aftermarket injectors require different insulators?

I've still got a set of new 750cc Delphi injectors on the shelf. I can take some measurements if you need some numbers to compare to.

I had 650's in the same stock OEM insulators.

I just tried it on another injector and it worked fine.

Looks like the ridge on my test injector is some how worn down.

I'm going to have to figure out how to get a good seal

I had a boost leak out of all my injector insulators when I first got the car.

Mine actually stuck to the car and I had to use pliers to get them out.

It might seem that the new ones don't fit as well cause they haven't had preassure put on them throughout the years.

And are the injectors OEM or are the insulators OEM?
I emailed fuelinjector clinic a while ago and they clamed that aftermarket injectors needed aftermarket injector insulators.

injectors are 720s
OEM Insulators my mistake in the previous post

My rochesters needed a different insulator. They were shipped with them when I got them.