Our 94 KWT300 rollback has an 8.3 backed with an 8LL, not sure on rear ratio, figure fairly low cause the truck tachs out around 85. Any the questions I have is. It has an HX40 & I'm curious is this the same HX40 on the 5.9's? Also how to turn some fuel to it? It pulls "fairly" hard now but of course would like a little more.

 

6B 5.9L do not have HX40s stock. they got HX35s with a stick and HY35s with the automatic. only the 6C 8.3L got a HX40 stock. but you can bolt an HC40 to a 6B no problem. I have one on my '95 6B currently.

what injection pump do you have on the 6C?

 

I bet it has a P-pump. Same mods work, but be super careful with EGT. That 8.3 is working a lot harder than a 5.9 in a pickup, you can't get away with lots of timing and fuel.

 

Yeah wasn't meaning the HX40 came stock on the 5.9's was just curious if the 5.' & 8.3 have the same flange size. Pretty sure it's a P pump.

 

That's what I was thinking, but swear it looks larger than those on 5.9's.. Then again it's been many moons since I fooled with a mech 5.9. Have an after turbo pyro & boost gauge on it already. I'm not wanting a ton of power, just a little more bottom end grunt. Most I ever gross is around 45k, pull the same equip with my 5.9 at times.

 

You could turn the low boost (aneroid) fuel out a 1/4 or 1/2 turn, that will give you a little more low end. I would not go any further then that though.

 

Check fuel pressure and make sure your shutdown solenoid goes all the way up. The 8.3L's are not as robust as the 5.9L we've had trouble with the two that we have on the farm this year. Be careful