I am connecting a multitude of test gauges to take some readings tomorrow. I have a 1999 454 Magnum, I cannot find the fuel pressure test connection anywhere! Where is it? Where is the most accurate place to connect the water pressure gauge on the block?

Thanks

The schrader valve is at the front of the fuel rail. On Horizon models, it is just about impossible to get to without taking off the plenum.

Dave

since I cant find it, I guess I have a Horizon model? figures...

Horizons have closed cooling systems

You will have to match an adapter for fuel. The entire fuel rail should have constant pressure so find an easy spot. Water pressure generally is taken at a block drain fitting. Fresh water motors again you will a have to make an adapter. I would think a good place to measure water pressure would be after the exchanger and before the tee to exhaust.
Jim