I am stumped right now!! I have a 68 Barracuda with LA360, bored .30 over, Comp Cam XE268, ported Magnum heads, and MP M1 intake manifold. Using a 770 cfm Holley Aluminum Street Avenger and Carter 120gph mechanical fuel pump GM6270 . So after 15 minutes of driving, when I slow down to 10mph...