JUST GOT A 289 FOR MY CAR....I GUY I KNOW RESTORES MUSTANGS BUT DEALS WITH BIG BLOCKS...ANYBODY RUNING 289 IN THER CARS?
A 289 and a 302 are the same block but the 302 uses a longer stroke. There are more parts for the 302 available for improvements and all the 302s have the 6 bolt block to bellhousing pattern. Some of the early 289 used 5 bolts and won't fit the newer transmissions and bellhousings. This is not to say a 289 is a bad motor - they are not. I built a 350 HP 289 back in 1969 (engine dyno tested) for my 65 fastback. It is just easier to find replacement parts for the 302 today.
The 302 block has a slightly longer cylinder wall skirts to handle the small increase in the extra stroke. This extra skirt also reduced piston slap and improved stability. You can put 289 rotating parts in a 302 but don't want to use 302 rotating parts in a 289. The later 302s/5.0 has longer lifter bores to accommodate the roller lifters. Personally I rather have the 289 shorter stroke...they twist faster. I have a 5-bolt 289 block and finding a scatter shield without paying an arm and a leg is the only draw back.
The 302 would rev faster - it has a lot more power to turn the engine around. It would also take a car through the traps faster, in less time, as long as the weights of car and driver were the same.
i swapped my stock 302 for a 289 that we stripped from an old ss pinto. Fastest time i have ran is 12.46 in the 1/4, but with alot of room to improve once we finally get the tuning of the carb right. I'm loving it