intake bore 1 11/16, tbi bore 2 inch
 

The Holley 670 unit says its a 2inch bore, the edlebrock performer intake says 1 11/16 bore. So what do i do? They have spacers for 2inch and 1 11/16. Help I'm ready to buy right now.

Also the add says 87-89 tbi truck will it fit a 92 lo3

just get a perfmormer carb intake and a spreadbore carb to TBI adapter plate from holley that is 2 inch

Adaptor provided
 

I know when I got my Holley I got the adaptor with it for the stock manifold.... I didn't need it for I had the Weiand intake... I looked around for the holley box but couldn't find it, but I believe they still include that adaptor when you get the TBI unit.
-Snowdog.
:D

Read this

and yes, the 2" comes with the adapter plat for the stock sized intake holes.