Originally Posted by rusty rockerpanels
... I also used the flex plate off 229 on 350 turbo tranny. Havent gotten it started yet but am beginning to doubt my thinking. Any imput ???
Don't use the 229 flex plate on a 4.3L, you will end up with a shaker. The 4.3L V6 and the Vortec 350 sbc have an external weight in the flex plate for balancing. Get one of these flex plates.
GM Changes to the sbc
(From GM website
1986 – The rear main seal was changed from a 2-piece rubber design to a 1-piece rubber design that used a mounting appliance to hold it in place. This necessitated a change in the flywheel/flexplate bolt pattern, as well as the need for an externally balanced flexplate/flywheel.