Im in the process of doing this, but was running the previous 350 with all the stuff I'll be running on the 383-cam, manifold, headers, etc. First of all, burning chips may seem the less expensive way to go, but because you'll need to burn (or have burned) many chips to get it right (most people burn one 3 or 4 times and get it in the ball park and call it good), you may want to go the way I did and give Dynamic EFI a call and buy their EBL Flash set-up. It allows you to hook your laptop into your computer and do all your programming in real time. Now, the learning curve is fairly steep, and I was pretty intimidated by it at first, but its not as bad as it seems. I was running an LT1 roller cam, and Edelbrock aluminum 4 barrel manifold with an adapter for the TBI, and Mid length SS headers. I also made an electric fan setup, and did the Ultimate TBI mods. After playing with the tuning for a while (to get it to run well, is fairly easy, but you'll play with it for a long time to fine tune it), I was able to pull down ~25mpg on the highway (the EBL allows you to enable lean cruise, btw). If youre going to run the stock air cleaner, be sure and eliminate the hot air flapper. Most of the ones Ive seen are stuck closed, and this is why most people get such good gains from flipping the lid on the air cleaner-even with the hotter air. The stock air cleaner flows more air than your TBI, so dont worry about choking the motor.
My 383 is going to run a much bigger cam (Comp Cams 268), and I got a TBI spacer off of a early 454 TBI. I am going to run a divorced vacuum referenced adjustable fuel pressure regulator that will make tuning waaaay easier, but just about everything else will stay the same.
I just dropped the motor in yesterday, and now I need to start hooking all the wires back up and finishing everything else. Hopefully fire it up soon.
