I have a 66 mustang with a 289 that i would like to upgrade to a 302. Which 302's will work. I here there are different block styles.
 Thans  

All 302 blocks will fit as they all have 6 bolt bellhousing pattern. The only difference in your 289 is that the piston wall was finished deeper in the 302 to accomodate a longer stroke. You can use a 289 crank in a 302 block but you really shouldnt do the opposite. Up to the late model 5 liter blocks all are pretty close although later models had the one piece rear seal. In, I believe, May of 66 Ford changed over to the rail type rockers so if your heads are rail type rockers you can reuse those also as they are the same.Pay attention of course to the compression ratio. Your early model 289/302 used a 28oz imbalance flywheel or flexplate,Ford changed over in 1985 to a 50oz external imbalance. There are some other minor changes but nothing that will preclude swapping in to your 66.
Early 289/260/221 engines(pre 65) had a 5 bolt bellhousing pattern, these are the ones to avoid for your application  

I have a 302 from a 1993 Ford F-150. It was EFI and has roller lifters. Can i use this motor if i use intake and flywheel from 289? Is other changes that need to be made?  Thanks  

Well I wouldnt recommend the stock intake from your 289 (although it will fit) but get an aftermarket manifold and carb like the performer and holley street avenger or edelbrock around 600/650cfm. You also need your flywheel rebalanced(any driveshaft shop can rebalance) to 50oz imbalance for the later model motor. Your truck motor may not have a fuel pump eccentric so check that ,,,and you might be forced to install an electric pump. Other then that you can make the swap it will bolt in, use your 66 engine mounts and it will bolt to your bellhousing and manual trans whatever that is. You have a clutch z bar that bolts to the engine, I have never used that late a model truck block but make sure its drilled and tapped for the z bar pivot on the block for your clutch , I think they all are but not positive. You could use a later model bellhousing and trans adapter and bolt up a cable clutch like the later model mustangs or you could use a hydraulic clutch if you dont want to stick with the troublesome z bar.I have no idea what the truck oil pan looks like but it needs to clear the crossmember in your 66 so you will probably have to change that. You will likely need the front sump oil pan from your 66 and the pump pickup to correspond. Cant think of any other problems?  

Thanks, great info! It makes life alot easier!  

Getting ready to drop 302 in car.With the flexplate imbalance, can i use flex that was on 302, or do i need to have 289 flex re-balanced ?
   Thanks  Jack  

Well you should use the flex plate from the 302 as long as the bolt pattern in it will bolt up to the torgue convertor, but check it for tooth count against the stock 289 if your using the 289 starter. Be very careful when bolting up because the torque convertor only bolts on one way. It might look like it will bolt on two ways but it wont. The convertor requires clearance for the drains on both sides.  Be careful when you put the convertor in the trans, it has to fit all the way back into the pump and that means it doesnt just slip in once and fit you have to rotate and push it in so that its all the way seated, you may hit two or three different particular drops(times when the convertor drops back while turning it). Also make sure you use the front dampener for the 302.