I have been told that a 12v lift pump can be put on a 24v and that it will increase performance because it can be "turned up", is this true? how reliable?

 

The 24v does not have the lobe on the cam that the 12v lift pump requires. Some aftermarket cams do have the lobe. The reason for putting the 12v lift pump on the 24v is more for reliability than power. It can put out more fuel psi than the factory 24v lp but the VP44 does not need very high fuel press, and too high can damage it. Too high fuel press at startup will also cause hard starting.

 

The pump you'd 'turn up' would be the injection pump. It too can be put on a 24v engine, but won't be cheap. Theres many threads on that on here. Do a search, and prepare for a lot of reading.