hey guys this is a ford thing but i really need help!!! i have a 78' ford f150 with a 400m engine and i had a cam go flat in my truck, so i replaced it with a 252-h compcamsand lfter set, i also replaced the timing chain with a non-retarded one.when i got the motor fired up, i had no oil pressure and the lifters wouldnot pump up, so i went to the parts store and bought ahi-volume/hi-pressure pump, my friend told me to check my main bearings while i had the pan dropped. i did and found the crank was severly scored.i had a friend that was parting out his 78' bronco, and i bought the 400m from him. it was completely stock and he drove it into the shop before we pulled the motor. i got it home and installed the rebuilt heads off my previous motor, the new cam, lifters, timing chain, and hi-volume oil pump. i have also installed new rod and main bearings and they are within factory specs. i have also installed the oil pressure line from the front of the block (hi pressure right out of the oil filter to the sending unit at the rear of the motor, and i can not get any oil pressure reading. i have both a factory and a mechanical gauge that i have swapped twice to verify that it is correct. i pulled the oil filter and cranked it over and oil gushes out like crazy. and i have also pulled the sending unit and now oil comes pouring out of there like crazy too. but i still have no oil pressure. i pulled both valve covers and i have absolutly no oil coming to the top end of the motor. what is wrong with this thing!?!?!?