Nobody that I know of makes a spacer for the 2.1. Your best bet is the have one made locally. I would have it made taller than you think and trim it down as you see fit.I'm currently working on upgrading my 2.1 kenne bell with a 2.6 mammoth inlet. I was able to get a 1" spacer installed while Kenne Bell was giving it a little rebuild. The 1" spacer works ok with my Fore fuel rails. However it doesn't give enough clearance for the intercooler fittings on the intake manifold. Does anyone know somebody that actually makes spacers for this swap? Looks like i need at least 1 1/2" spacer.
I thought about just putting plugs in the holes and relocating the fittings to the back as you mentioned.Nobody that I know of makes a spacer for the 2.1. Your best bet is the have one made locally. I would have it made taller than you think and trim it down as you see fit.
Another option is what a member here did years ago and have the holes for the intercooler fitting welded shut and then tapped new ones on the very back. Basically instead of the 90 degree fittings he just had straight fitting off the back of the boss.
Looking at my manifold I would be concerned with the plugs possibly blocking flow or causing a thread engagement issue on the new holes.I thought about just putting plugs in the holes and relocating the fittings to the back as you mentioned.
