Ok I think I got it. So I need to find a bell housing for a t-5 that was already attached to a 258.
Now as for a radiator will I need a new one I'm assuming i'll need one for a 258?
Also when I go to the parts store to get parts do I search for? (Meaning the engine is from a different car so will I have them search for that vehicle or just pick a year of cj7 that the 258 was in)?
If I am understanding you correctly you can't just walk into a parts store and order everything you need to drop a 258 into a Jeep. The hard parts are no longer made. Remember you own a vehicle from a long dead auto manufacturer and it's 30+ years old anyway.
258's were used in Jeeps from the 1972 to 1990 in Jeeps. 258's were mated to T-5's from 82 to 86. The 151 was a GM engine that AMC used since they did not have their own 4 cyl at that time. A 151 bell housing will have a GM bolt pattern to the block not an AMC bolt pattern. Once you have a 258 in your Jeep you would buy service parts for what ever year the engine is. Unless you use the same year engine as your Jeep or convert the engine to be as it would have rolled out of the factory in your model year Jeep. A footnote engine packages at that time were pretty much the same across models. An 82 Eagle 258 is not really any different than an 82 CJ 258. Some accessories (Alternator brackets, P/S brackets, oil pan) and plumbing will be different due to body designs. Some key pieces will be CJ only parts and they will not be available as service parts. Motor mount brackets for one. There are 4 of them 2 that mount to the block and 2 that mount to the frame. the mount itself is a service part that can be had at most parts stores.
You can figure anything from the bellhousing to the fan on your 151 as not interchangeable. the only exceptions i can think of are the alternator and the P/S pump. But their mounting brackets are not. You would have to acquire those brackets. Also you will have to do some wiring work to the engine. The 4cyl harness will have to be modified somewhat to work with the 258. the easiest way to do the conversion would be to find someone that is removing their 258 and installing a V8 since everything I just spoke of, they can't use on their V8 conversion. Radiator can be any 76 up CJ with a 258 or V8 but you have to be careful with V8 rads since there is not a lot of room for all V8 rads. example: I have a 3 core rad in mine and it is very tight. With electric fans there is only 1/2 inch clearance between the fans and the W/P pulley.
1981 Jeep CJ7 4.0 HO, AX-15, D300, D30, D44, SOA
1977 Chevrolet C/10 step side 454 TH400 3.73 posi