6PSI @ 5200RPM 454 tuned in the water by Dustin, runs great but fowels plugs halfway through the season. Rv9yc's, stock ignition, running rather cool (especially @ Tahoe). Drilled cold t/stat may get to 130F-140F tops. Blew-up the engine once due to stock injectors and not enough fuel at a 95% duty cycle. Bigger injectors, fresh motor, tune-job and runs great. Plugs are very cold, should I step up one range? Water temp could go up a tad. I have a signal conditioner EC0051-1 not installed. Or should I just leave it alone?

Since Dustin tuned it I would ask these questions of him. He may have the water temp and cool plug setup that way for a reason, i.e. keep it from dentonating.

Take a look at RunningHots engine problem 'thread' to see what can happen when not setup correctly. Your suggest changes could cause that type of problem, assuming your current setup is done that way for a reason (hearing of Dustin's experience, I would assume he has a reason for it).

Rick

Ditto. He may have tuned it not to need the sig cond. It's better to foul a set of plugs than melt a piston or detonate. I don't run a t-stat at all. Iron heads need to stay cool as possible. There needs to be a book written for all the shlt you should do!