I am going to install my POD's this weekend.
Being as that my engine is a 1990 model, I will need to use the adaptors.
What I want to know is:
DO I also have to use the washers, and if so what thickness is recommended?
I thought I read somewhere that if you use the adaptors, you don't need the washers.

 

You are correct, if you use the adapters you DONT need the washers.

 

Rockjeep's right, you don't use washers with the adaptors. The adaptor is the washer.

 

Do the POD's come with the adapters?

 

Nope.
You have to order them seperatley.

 

Adaptors cost $6-$8 each X 6.

 

I take it that you need adapters because the heads are different?

I can imagine that adapters would be like those anti-foul spark plug socket things that I used to have on my 305 GMC Suburban?

Do they reduce performance?

 

IC'd heads have 7mm injector holes, nonIC'd heads have 9mm injector holes. POD's have 7mm tips. The adaptor takes it from 7-9mm. I don't think they would reduce performance. Only thing would be you don't get to use different washer sizes- ie cut down on idle haze by use of the thinnest washers. The adaptor is probly equivalent to the thickest washer in an injector install kit.