HELP! Starter on my 1995 LS 400
 

When I turn the key I get only a clicking noise, after trying multiple times it would start. Went on for months now it just clicks. Battery is ok, checked connections ok. Could this be starter or the solenoid? Not sure what to attack. There is a metal pipe attached to my rear coolant crossover pipe, seems to go straight down to I can't tell where, can't pull crossover off because of this. The bolts holding it on are impossible to get to, if they did come off you could never get them threaded back on! Not sure what to do at this point. All of the illustrations I have looked at do not show this pipe. Have the 4 bolts off but will only move very small amount, and I can't remove the crossover pipe. Looks like that pipe attached is the reason. Do I unbolt this pipe somewhere else? Possibly missing something else? Read, watched video, never heard anything about removal of this pipe. I have tried crowfoot wrench from front of crossover and rear, can't get on the starter bolts. Some say you can others say you must remove. I have restored many older muscle cars but this is something else! Please help if you know where I am screwing up!

Hope you get help