[ComposiMo]

You need the fuel rail spacers with the stock intake manifold... something along the lines of 3/8" thick or something.

I don't have the part number for it, but go to www.acuraautomotiveparts.com, then select a 1991 Acura Integra GS... doesn't matter about trim or manual/auto tranny or anthing... then go to the "Intake Manifold" page, and look at illlustration #008... "Fuel Pipe Insulator" Product Reference #9642

8)

 

[ComposiMo]

By the time your buddy getsdone machining them, you could have just ordered them from hondaautomotiveparts.com, and been done with it... for like under $5.

But hey, whatever

They are a hard plastic material.... not rubber. I've seen aluminum ones around as well, but most are plastic.