Since I'll be doing a complete rip down soon on our new stang I'm thinking this should be one of the first things I do once I get the engine out. Start with some added upper support right from the start and keep it. Car already has an export brace installed however not the monte carlo bar.

Question: With a 390 big block installed should I go with the stronger straight bar or the curved one? Thanks.

 

I'd go curved, I dont believe that the curved ones are "weaker" than the straights. If you have enough power to flex the entire chassis hard enough to mess up the monte carlo bar, you'r gonna have bigger problems elsewhere.

The curved ones offer more room for airfilters (perhaps important for u)and clear the distributor.