dont quite know for sure on the swap over Kit...but if i were in your shoes and was thinking about doing the same thing as you i would be thinking this route.
1- front Tubular 'K" member..all bolt in stuff..this will give you much clearance with the headers plus take about 75lbs off the front end..( a kit is sold for this)..can be installed on a Saturday.
2- i would go with a front motor plate..and welding shop can mount this plate with a dummy block sitting in the car...this will elimnate a bunch of fabrication or guess work...unless you can find a direct conversation that will bolt up to the v-8 motor mount spaces..if the v-6 car has v-8 spaces..etc..
3- i would go with a 350 or 400 turbo..Rossler makes a great street strip tranny..you can get your speedo to work with this tranny.
this is extactley how i would pursue this situation.
Brian
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Bjuice..
"I'M YOUR HUCKLEBERRY ! "