855/350 mod questions

Personally I would leave it alone.
I have seen lots of engines boosted to get that extra bit of Power, then when the exhaust manifold cracks they loose more than they ever gained and are using more fuel.
As a 350 it will live, boost it up and it will not.
Just a thought!

 

The shims are for governed rpm, they don't affect fuel pressure or volume.
The button limits fuel pressure.
The adjustment screw in the throttle shaft adjusts fuel volume.
The AFC adjustment (under throttle shaft) adjusts fuel delay.

 

These motors can run very well and live a long time turned up. Its been done forever. I love these guys who always have say not to do that. Ur gonna blow it up! Whatever! U leave urs alone and let us do what we want. U can drill the end of the throttle shaft out and theres a screw in there u can back out and get some more fuel from . Im not sure of the rest of the tricks but I know theres ppl on here that do. That motor will make pretty good power without any trouble.

 

Look up pittsburg power, they seem to know a lot about the 855 and getting good power and economy out of them.

 

The shims and button are located in the governor housing on the lower backside of the pump (4) 1/4" bolts to remove. Add shims and/or install heavier spring to increase rpm. 2300 rpm is plenty good, no need for more. I had a guy insist on 2700 rpm on one and he replaced plastic engine cooling fans monthly (the blades would fly off). He came back and had me set it at 2400 rpm and it lived.

The button is also in this assembly. It is a controlled bleed. The smaller number (smaller bleed hole) the higher the fuel pressure will be in the rail. A #8 button is popular. Pick your own poison.

The fuel volume can be adjusted by first drilling and removing the steel ball in the end of the throttle shaft. Turn screw out or counter clockwise for more fuel, 1/4 turn at a time. The amount of fuel you can get into the cylinders will be limited by the injector inlet orifices unless you change injectors.

The AFC adjustment is under aluminum cover held to pump with rivets and is just below throttle shaft. Adjust counter clockwise for quicker throttle response, 1/4 turn at a time up to a full turn or so.

Caution: If the pyro needle moves faster than the tach needle when you hit overdrive, you'll burn it down sooner or later.

 

Governed rpm is on your engine tag, most likely 2150 rpm, that's as high as they went, Formula engines were 1950 rpm.

If you write down the numbers on your fuel pump tag, including CPL # , a good injection shop can tell you what's in it, and guide you on options offered to get you where you want to be.

Safe here is a relative term and I would need to burn one up to know, but I never have, so I can't say. I will say that I've set them up scary hot, cracklin and rattlin as requested and I didn't see them back or hear of them smokin a hole, but the pyro would go ballistic in overdrive just bobtailing.