You have to replace the pistons and cylinder liners??? If you're replacing pistons, there's no need to touch the IP or remove the chain from the IP sprocket. If you're replacing cylinder liners, the crank has to come out which means the chain and IP have to come off the block. There's no way to keep things indexed. You will have to set IP timing when installing the IP. Setting initial IP timing is an easy task compared to resleeving the block.

Is it worth your time and money to do that work? It might be cheaper and definitely easier to find a replacement engine.

Sixto
87 300D