first gen 12 valve cummin
 

I just bought a 92 d350 136k box a title wanted to change the fule pin and turn the dile but does that make it less reliable wanted to get 50 to a 100 hp more out of it but its my daily driver and I hual fire wood with it looks pretty eazy on you tube any lnfo is helpful I am cummins rookie ues to work on my 6.0 powerstroke all the time

no changing the fuel pin and idle wont make it less reliable.
On another note,is the killer dowel pin dealt with?

What is the dowell pin I dont know any thing about these motors

Basicly there is a pin inside the timing cover housing that keeps the housing in place. On 12valves they've been known to back out and cause damage. If it copmes out it can
#1)fall harmlessly into the oil pan
#2)the pin can fall between a couple of gears causing gear damage and crack the housing cover.
#3) the pin can fall between other gears and cause valves to smack the head,ect.,ect.ect. (basicly it could ruin the motor beyond repair.)
If you go up to the search section and type in killer dowel pin it will bring up more info on this.