I know of all the bad press these 3.slows get. I hope some of it is unfounded, lots of those things running around. I have two center cylinders with low compression, 85 psi and 125 psi. on my 89. I checked out the valve lash and found both exhaust valves too tight to get any sized feeler gauge in between. I don't have the special plyers to depress the valve, was thinking of making a tool, any ideas? Biggest question is with an engine with only 53k on it, what are the chances the exh valves are tuliped? When I pulled the injection plenum, HUGE deep mouse nest, full of home insulation, nuts, etc. Bet this helped heat up the center cylinders...Thanks in advance, John in NH