Funny, I got the wrong size from the dealer as well, wonder what the deal is?

Here's a how-to:
http://www.4x4wire.com/toyota/maintenance/idler/


'87 4-Runner--DD/wheeler, 4.3 swap coming soon
'89 Supra--E85 powered 2jz NA-T Swap, 533rwhp 497ft-lbs
'89 Festiva, turboed BP swap powered by megasquirt