I was wondering if any aftermarket companies manufacture an EGR block off plate for the LT1? Right now I just have the stock piece and I cut off the metal tubing that runs to the exhaust manifold and capped it with a rubber cap and a hose clamp. It works but I would like something more professional...

Make one from some aluminum plate. Use 5/16" or thicker.

You can just use some sheet metal and gasket material or sealant to block off the piece on the intake manifold

ask the guy that sells the LT1 intakes that are modded for our cars...

they use LT1 block off plates... he probly can sell you a nice one.

I have that intake setup...he just makes plates out of 1/8" aluminium and seals them up real tight with RTV...works really well.