Well, I plan on boring out the hole just smaller than what i want it. i will then make a simple hone and use it to make the bore diameter do my exact likings, as well as create a finish that will seal to the plungers well.
Also, why do the plungers have to be chromed? Why couldn't i just machine some out of some hardened steel?
Thanks for the input!
I tried to do what you are thinking of doing. I was able to get a pump to pump some fuel, but it didn't last long under pressure of poping injectors. The reason injection parts are chromed is that they operate under extreme pressures so they need an incredibly hard surface to keep from wearing and keep extremely close tolerances.
There are pumps out there that have been custom modified for huge plungers... you just have to fork over the $$ to get one. I've heard reliability leaves something to be desired as well...
A stock 6.2 pump has .290" plungers in it, a stock 6.5 has .310", the marine pump has .330", and I can't remember the spec for the 4 plunger pump. Basicly a 6.2 pump is good for around 230 flywheel HP, 6.5 pump 290 flywheel HP, marine pump 350 flywheel HP, and the 4 plunger around 400 HP. These are rough estimates based off past experience and knowledge passed on from others.
If you have extra time, an old 6.2 pump, and access to some equipment I'd say go for it. Maybe you'll find a way to make it work without chromed parts