you'll have to worry about the valvetrain more than likely before you gotta worry about the bottom end. but i wouldnt push stock stuff much more than 5500
5500 is right if it's stock. That's when the rod bolts start to really stretch. The crank will go much farther than that. But remember the more Hp you make generally the lower that number gets.
A solid lifter unit will turn 7000 with no problem but they really stop pulling about 6200 so no need to go any higher unless you really have a high dollar motor.
Keep hydraulic motors lower as valves will float for the first few times. After that it may get ugly.
stock rods with 5/16 arp 2000 bolt and a stock crank I say is good for 8500. Thats because ive been there and done that with three differnt 289's. The only rod failure was because of a broken arp 8740 rod bolt that was incorectly torqued.
Now I didn't say they would break. Just said that's when they start to stretch. I've had stock rods with arp bolts. It saw 9400,oooppppss. Tranny missed 3rd.
Your biggest problem with the stock 289 is the valve springs not keeping up with the high revs... Keep it around 5500, unless you're looking for a good excuse to drop in a new motor. Remember you have a 30+ year old engine...
First your valves will start to float, then once you get to around 6000/6500 your block will start to twist. Now, I donno what year your block is, but I know back in the 60's Ford had a problem with there 289/302 twisting once you got that high. A main ladder is a great way to prevent this however.