Is it necessary to upgrade the AFM along with the throttle body? Do you need to installthe LS1 throttle body (85mm) with an adapter? Is this too big for a standard motor?

While we do supply an adapter to suit an LS1 throttle body adaptor to suit as shown in the link below:

http://www.maceengineering.com.au/epages/shop.sf/en_AU/?ObjectPath=/Shops/mace/Products/TB606

I would not recommend it on a bolt-on V6 engine, due to the initial cost of installation plus the cost associated with the custom tune required for it to work. In this context, I would certainly recommend one of our larger bored-out factory throttle bodies as shown in the link below:

http://www.maceengineering.com.au/epages/shop.sf/en_AU/?ObjectPath=/Shops/mace/Products/TB0001/SubProducts/TB601