check here for your adapter.
http://www.advanceadapters.com/categories/engine-to-transmission-adapters/233/

as a note, you may be better off and end up being cheaper to sell your T18 and get an SM420 or SM465 to mate to your 350 and use all factory parts.


Mike
1955 Chevy 6400 ex-flatbed (no bed now!) sold September 2023
In the Stovebolt Gallery
1958 Chevy 6400 flatbed W/dump
In the Stovebolt Gallery
1959 Chevy Suburban Owned for almost 20 years, Daily Driver -- sold May 2016
In the Stovebolt Gallery

Sufficient unto the day is the evil thereof