Weird Fuel pump problems....

I just installed a 5.3ltr 4L60E into a 72' El Camino....I used an external Walboro Fuel pump and the Corvette fuel filter regulator...The first time I switched ignition ON fuel pressure went to 58 psi....So everything was good until I fired up the motor and the fuel pressure shot up to 100psi and didn't go down! I changed Fuel filter regulator, checked for any kinks or sharp bends in fuel line and dropped fuel tank to make sure return line wasn't clogged or something but I didn't find anything wrong!!! Fired motor up again and pressure shot up to 100psi again...WTF!!!
I'm using 3/8" fuel line for return and pressure side...Any Ideas??? :lookaround:

Do you have the supply and return lines swapped...?

I checked that a couple of times and NO they're correct....

No disrespect, but are you sure the inlet outlet and return are correct?
Last time we did one of those setups we hooked it up wrong. it doesnt go how we thought it would haha..

just something to double check.

besides that, you already checked the return, maybe try another filter/reg?

I found the problem, the return line was plumbed to the emission port/vent instead of the return which is almost completely sealed off :chair::chair::chair:
Now all the spark plugs are fouled...I guess that's what I get for trying to hurry this project up!!!:redface:

DOH!!!

glad you figured that out... i forgot to mention we did that on one of our swaps...
just thought about it too.