So I cant get the fuel pressure to go lower than 8psi. I have a holley external electric fuel pump and holley bypass regulator. the carb is a Quickfuel 850. All of the fuel lines are new. The 8 psi was according to the pressure guage at the carb, maybe it's bad? Before I had the electric pump and regulator it was between 5-6 so I don't know. Any ideas. By the way it is on a 377 SBC, 640 hp on the dyno.

 

What's the PN of the regulator to you're using? And which Holley pump?
Where you using a mechanical pump prior to this? If yes, did it have a bypass line?

 

What’s PN? I have the Holley 12-890 and the Holley 12-845 regulator. I did have a mechanical pump but no bypass.

 

Sorry. PN is short for part number.
I've seen regulators installed that were assumed to a by-pass style but weren't. You've got that covered though.
If the return line is properly sized ( -6an or 3/8") then the issue may be with the gauge as you mentioned. Other than not being adjusted properly (and assuming the pump polarity is correct) there may be some debris that's gotten inside the regulator. Teflon tape can get in there and mess things up.
EDIT: Just read this as I'm sure you have too.
This pump is not designed to use a standard conical seat style union in the inlet or outlet of the pump. Example: Part # AT981508ERL. Use of this style fitting will block flow and WILL lead to poor performance and pump failure. The ONLY correct fitting to use is a contoured port fitting with an O-ring seal such as :Part # AT985008ERL.