What makes you think it has a dead cylinder?
Investigate every avenue, pull the valve covers, inspect rockers and pushrods, spin the engine over and see if things work as they should.
Trobleshooting is 99% of fixing a problem.
Simple things get overlooked because it "seems" like a major problem.
The last engine I swapped out, I took someone else's word that the engine was "knocking", put in another engine, drove the truck home and sold the old engine as a core, only to find out all that was wrong was a broken pushrod banging around.
What should have been a $30 fix, turned into an engine swap and the replacement engine cost me $1500 and it used 12 GALLONS of oil from Barstow CA to here.
If only I had taken the time to troubleshoot the engine myself.
Mark.