I bought all lines, from tank to carb, for my 70 300 from Inline Tube.
Mopar Catalog Page 17.
The pump to carb is the same for whatever engine you have regardless of C, B or E-Body, so you'll likely have to go to one of those B or E pages to find that line. That's exactly what I did. Here's my order from Inline for everything. Lines, clips, screws, etc.
1 Sale CYF6901 - 1969-70 Chrysler Newport/New Yorker/300 124.0" WB 5/16" Main Fuel Lines 2pc, OE Steel $ 79.00 1.00 ea $ 79.00
2 Sale DBE6805 - 1968-71 Dodge B-Body 440CID 4bbl Carter AVS 5/16" Pump to Carb Lines 2pc, OE Steel $ 24.00 1.00 ea $ 24.00
3 Sale CLP109 - 5/16' Single Flat Mopar Line Clip $ 1.25 11.00 ea $ 13.75
4 Sale CLP202 - Clips & Clamps - 5/16' Hose Clip Spring Clip Black $ 0.75 5.00 ea $ 3.75
5 Sale CLP203 - Fuel Line Pinch Clamp, 3/8' ID Hose Spring Clip Green, Each $ 0.75 5.00 ea $ 3.75
6 Sale CLP143 - Transmission Line Clamp - 5/16" or can hold 3/16" tube with spring, galvanized, 1/4" wide $ 0.75 2.00 ea $ 1.50
7 Sale CLP174 - Brake and Fuel Line Clamp, Single R Style 5/16' No Tab Painted Blue .330 Bolt Hole 3/4' Wide - Also Used for 3/16' Tube with Spring, Each $ 2.50 4.00 ea $ 10.00
8 Sale CLP150 - Clips & Clams - Line Clamp Bolt - Black $ 1.25 4.00 ea $ 5.00
9 Shipping SHIP G70-5 - SHIPPING & HANDLING OVERSIZE GROUND $ 48.74 1.00 ea $ 48.74 Date Payment Amount 07/02/2018 VISA $ 189.49