MY SON JUST PUT A REBUILT LONG BLOCK 351 IN HIS '92 FORD TRUCK, THE OLD ONE WAS COMPLETELY WORN OUT. HIS COMPLAINT IS THAT THE NEW ONE ( SEVERAL HUNDRED MILES NOW ) DOESNT RUN ANY BETTER THAN THE OLD ONE AND POOR GAS MILAGE. HE DROVE AN IDENTICAL TRUCK WITH A 302 IN IT AND SAYS IT WOULD RUN CIRCLES AROUND HIS 351. HE HAS CHECKED COMPRESSION (130 ) ALL AROUND. HE HAS CHECKED FUEL PRESSURE ( 35#). MADE SURE THE CONVERTER WAS CLEAR. TIMING AT 10 DEG. WHAT ARE WE MISSING ? HE ALSO HAS SOME KNOCKING OR TAPPING IN THE FUEL RAILS, COULD THIS BE RELATED ?

 

35#'s may sound like enough,but it might not be enough. The pump ought to be able to pump at least 45#'s with the regulator unhooked. The pressure after the regulator is important also,which may indicate a faulty regulator.The ticking you hear in the fuel rail is the pulse of the injectors.I believe a higher fuel pressure will quiet down the injectors.Also verify the fire order which is specific to the 351W. I have seen mis-prints in tune up books already.Double check two diffent sources for the fuel pressure and fire order.
Phillip

 

When you check the timing make sure and goose the throtle and make sure the timing is advancing. I had a truck that wasnt advancing the timing and it ran like a real dog.
Good luck.

 

A couple of things: Did he change cams? 302 and 351 cams will mix but they have different firing orders. Is the distributor in right...these engines will run being one tooth off, but will be way down on power.