I dont buy that... I think the reason alot of the older stuff stayed together(in the case of 289s) is because it was leading such a fabulous life of mediocre VE's and so forth. Hell, the 289 has been around a LONG time, and look the progression of Mustang racing. In the early 90s the big boys were running in the mid 10s with a bunch of off the wall experimental type stuff. Block splitting didnt really become common place until the mid-late 90s for the Ford. If the 289 block was the hot lick cure I think you'd have heard of ALOT more people doing them.
I dont think there are alot of people splitting 5.0 blocks while naturally aspirated. Even though superchargers have been around for a long time, its not like you can run a significant amount of boost on a roots on gasoline, with a carb and mechanical distributor. I have the distinct feeling if you took the HCI, blower(or turbo) and injection from a block split 5.0, and stuck it on the 289 it would suffer the same death.

289s are cool, and nothing wrong with them. But I dont think they are necessarily anything special. Get one at a great deal like Pat is getting, cool. But giving up displacement to increase RPM ability(while acting as if the 289 is somehow better) is not my thing. But if spinning to 9000 rpm is much more important to you than just making cheap power, go for it. The Honda guys do.

 

*sigh*
Great, you got a 5.0 pan. I was just telling you to be aware of the difference since the dipstick goes in the block, not the pan. You will HAVE to find a place to install the dipstick, as I cant remember if the old blocks even have a plug for a rear sump stick..

I wasn't tryin to talk you out of it, I could give two shits what your put in your car. Run an old 221 for all I care. But my first engine in my 79 was a 68 or 69 302, and there were things that were different that need attention. I think when I went 351 the stick went in the pan.

 

EEC IV is sqeuntial not batch/bank. You actually wont have an issue. We had a customer with a 89 gt that had a efi motor but a solid roller with the old 302 firing order. It was a builty 347 with a Vortech and it ran fine.