Choosing to repair or replace an engine

[Native]

replacing the front mail seal: 1. pull balancer, 2. pull seal, 3. replace seal, balancer, 4. recommend using a NEW balancer ~ $150 (less balancer)
rear main seal: 1. drop the oil pan, 2. remove crank journal, 3. use the tool to remove and pull new seal, 4. reassemble ~ $200

Jegs long block: these are typically pretty generic; possibly drill and tap holes, locate diff part at junkyard, purchase some expense part cause old one doesn't fit; shop will charge a FORTUNE. you might have trouble with manifolds, brackets, oil pan, etc.

[birchyboy]

replacing the front mail seal: 1. pull balancer, 2. pull seal, 3. replace seal, balancer, 4. recommend using a NEW balancer ~ $150 (less balancer)
rear main seal: 1. drop the oil pan, 2. remove crank journal, 3. use the tool to remove and pull new seal, 4. reassemble ~ $200

Jegs long block: these are typically pretty generic; possibly drill and tap holes, locate diff part at junkyard, purchase some expense part cause old one doesn't fit; shop will charge a FORTUNE. you might have trouble with manifolds, brackets, oil pan, etc.

Do you have a link to the service manual that you're referencing?