Mr. Gasman, i DO have expirience with LPG systems.
I have more lincolns, and one has a 300A mixer, and the one i want to switch the engine from, had a 300A system as well, and i converted it about 2-3 months ago to a holley valveplate and a impco 425.
We are not allowed here to use the vacuuum-shutoff valves, and use the electrical ones.
The problem with the LP gas shops around here, is that they're not familiar with such engines, and directly scream: " can't do it" or "impco 425".
Here in the Netherlands, the average engine is the size of a milkbottle....
There's just simply not much expirience in systems for such engines, and besides they calculate enormous amounts for such systems, IF they want to install them.
Add the fact that i'm handy and curious, i really want to make it myself, and gather as much info from forums like these, and make my own system.
So, any info you can give me is very highly appreciated!

Thanks!.

AnOldDog:
There are KB 138 pistons in them now. They have a dish from 22cc's in them, so flattops would gain some. The highest CR i can make is 11.5:1 with the KB401 wich have -11CC dome's...
They cost quite a bit however, so my intention was to get the engine fully running and drive it, and then, when i want to, open it up again (what a work... easyer to do when it's in my barn...) and change pistons..

maybe there are others that know where to get them for a reasonable price, or better alternatives?
16:1 seems quite high though for LPG. In Netherlands LPG is a mix of butane and propane, and has a mixture of 40/60 and 60/40 depending in witer or summer.
Also it has some impurity's, wich lower the octane.
If i'm right, the octane of LPG here is 108Ron at it's best. So lets calculate with 103-105, then i think 16:1 is on the risky side (and not achievable with the hardware available, i guess...)
correct me all if i'm wrong. thanks!