Re: TBI or MPFI?
I am going from memory, and I have built too many small blocks to remember them all, but it was an '80's carburated engine short block, that we built and installed into a later model Mustang. We used a multiport sequential port intake system and the firing order of the old model, but new engine, was different from the 302HO and 351 engines, and I did have to change the cam.
You are correct that the CFI engines have the same firing order, they are "newer", and I doubt if it will be a problem for the web member who requested the info, but it is something he should be aware of. The old firing orders started with 1-5-4 (same as all old small block 221, 260, 289, 302, + the 460's and the FE Fords, I still have a '66 427), all newer engine firing orders start with 1-3-7----- (I don't recall the entire order, but check your manuals to be sure).
Sequential injection will not produce more horsepower, but it (usually) will provide a cleaner and smoother running engine. In my opinion, however, it is not worth the cost unless you have most of the parts from a doner car or the car you are modding is a real "keeper".