I have etec 200's on my 400, kinda like your 383 slightly larger. the heads are ported now but in stock form it was a hugh wakeup on my stock 400 with very mild cam and dual plane air gap before the rebuild. The roller cam will help alot and should be very streetable. My current setup is a 406 ported etec 200's, customs cams solid roller with 264/272 duration and .632/.632 lift 10.5:1 compression, single plane intake, pushes 650hp don't know what it will do with the 150 shot i have on it yet. But in short the etecs have potential and the roller cam makes good power and the dual plane air gap is good for low end power, i drive my car on the street all the time, you will like it.