Sounds like your pay burns a hole in your pocket like me
No puller required. You should be able to easily do it without removing the radiator. If you had fat AU thermo fans on with a big radiator, it would be tight.
The original crank pully is bolted to the harmonic balancer with 4 bolts inside the middle - stick your hand in and have a feel. Don't undo the big balancer bolt in the middle. Then just bolt the gilmer pully on.
The water pump pully/fan is connected to the water pump with 4 long bolts. Undo them, remove the pully & fan. Again, bolt the gilmer pully on.
Oil leak from the crank area could be a few things - very common though!
1. Seal on the crankshaft. This is connected to the timing plate which sits behind the balancer.
2. Blown front sump rubber seal or sump gaskit.
3. Leaking between the timing plate cover and block.
You could degrease the area and then see where it originates from. If you have an afternoon, you could fix it in a few hours. Remove water pump, balancer (with puller!) and timing chain cover. Replace crank seal (knock old one out and tap new one in). Throw away semicircle rubber seal around sump. Scrape all old gaskits off block face.
Clean area THOROUGHLY with parts cleaner and clean rags. Instead of replacing the sump rubber seal I use a heavy duty/high temp RED engine gaskit silicon. No need to remove the sump. Run a fat bead along the sump and the groove on the timing cover when assembling and let it set 24 hours before starting. TruBlu's guarantee not to leak!!