If one is trying for more power, and is on a somewhat tight budget, and isn’t willing to use an aftermarket manifold and headers, along with a little mild porting on the heads…….then imo, “making more power” isn’t really that high of a priority.
If you want it to look stock, and have a noticeable improvement in power over stock(improved seat of the pants feel)……..then add cubes.
Just to reiterate RAMMs initial thoughts on the TQ output…….
The factory rating of 425ft/lbs is a unicorn.
A 100% stock 383, run with factory exhaust, isn’t going to make that.
That being said, I haven’t found the 383 to be an unwilling foundation for respectable power output after receiving typical the usual hot rod treatments.