replacement engine year?
If your replacement engine is a 2001 or earlier with the orginal camshaft timing components or a later engine with more than 50,000 miles on the timing components I suggest replacing all of the guides and tensioners. Since it is almost impossible to purchase the camshaft guides without purchasing the entire cassette (chain, sprockets, guide assembly) and since you can't replace the camshaft guide without detaching the camshaft sprocket I suggest you replace all of the primary and camshaft components. If you have 4WD with the balance shaft you may want to just replace the tensioner and guide since I think there is a lot of work to replace the balance shaft chain although I've never done it because I don't have one.
Anytime you disconnect either (front or rear) jackshaft sprocket, or the left or right camshaft sprocket the camshafts should be timed. While it is possible to time the camshafts without the tool set, I think the tool set is worth obtaining. It decreases the complexity and reduces the risk of incorrect timing that can result in valve damage. Even with the tool set the process is not simple and even some mechanics in repair shops not familiar with the process have destroyed an engine. The tool set includes a chain tensioning tool that makes the chain taught when timing the camshaft. The normal spring/hydraulic tensioner does not apply adequate tension for timing when there is no oil pressure.
