i highly HIGHLY do not recommend buying a v6 so that you can do a v8 swap. search a little on this site to figure out if you really want to go through with it, youll probably find that its a lot more of a headache than just going with a v8 in the first place. buy the v6 if u want a v6 and buy the v8 if u want a v8.
on another note i do recommend the 8.8 rear. on average our 7.5s(even with tlok) will likely crumble around 300tq. thats not saying it will happen but its pushing it, all you need is the right launch and bye bye mr 7.5. might die at 400tq, might die at 250, but u can always wait and see if it dies and then go for the 8.8 down the road. i also recommend looking into beefing up your tranny with g-force components or something from
www.astroperformance.com , might have to call em up im not sure if the site is 100% done yet.