I am leaving my 74 stock 350 (145hp) and stock exaust manifolds but I want the aggresive sound. Will the true duel flowmaster 2 1/2" sound good? Or other?

Personally I don't like Flowmasters that much. The "hollow" sound bothers me. But, if you have stock manifolds the exhaust is probably toned down enough that the Flowmasters might sound good.

Flowmasters sound real good with manifolds.

Flowmasters sound good on anything