Did you use ruber line all the way or rigid line? I'm asking because tank inc have a line kit with the filter and all the fitting to instal a FITech system but its 25f of ruber line. Also I talk to a local guy who I tinking is a perty good mecanic he he not sure about having 2 perssure regulators on the the same fuel system and he worry to about the return line not beeing plug in the trottle body. Im going to call the FItech support since they answer e-mails.
You can use rubber lines but it is not advisable as a long term solution. You can also use SS braided line (or any of the modern hi performance lines out there as the SS braided can be a pain to work with). The main issue with running "soft" line such as rubber is that it is subject to damage from road debris, scraping, etc. Also rubber lines can degrade over time internally.
As to the regulator issue, I am not sure what you are referring to, you only need one regulator on the return side.
70 Challenger RT 440-6, 73 Cuda (under const)
05 Durango, 99 Dakota, 01 Ram 4x4, 14 2500 4X4, 10 PCP Challenger RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR, 61 Jeep FC170
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